Some mostly trivial PEP8 pedantry.

git-svn-id: http://svn.stsci.edu/svn/ssb/stsci_python/stsci_python/trunk/stwcs@12320 fe389314-cf27-0410-b35b-8c050e845b92

1 files changed, 211 insertions, 158 deletions

diff --git a/wcsutil/headerlet.py b/wcsutil/headerlet.py
index e38b919..beead15 100644
--- a/wcsutil/headerlet.py
+++ b/wcsutil/headerlet.py
@@ -12,44 +12,44 @@ logger = logging.getLogger('stwcs.wcsutil.headerlet')
 
 def isWCSIdentical(scifile, file2, verbose=False):
     """
-    Compares the WCS solution of 2 files. 
-    
+    Compares the WCS solution of 2 files.
+
     Parameters
     ----------
     scifile: file1
     file2: file2
     verbose: False or a python logging level
-             (one of 'INFO', 'DEBUG' logging levels) 
-             (an integer representing a logging level) 
-        
+             (one of 'INFO', 'DEBUG' logging levels)
+             (an integer representing a logging level)
+
     Notes
     -----
-    These can be 2 science observations or 2 headerlets 
-    or a science observation and a headerlet. The two files 
+    These can be 2 science observations or 2 headerlets
+    or a science observation and a headerlet. The two files
     have the same WCS solution if the following are the same:
-    
+
     - rootname/destim
     - primary WCS
     - SIP coefficients
     - NPOL distortion
     - D2IM correction
     - Velocity aberation
-    
+
     """
     if verbose == False:
         logger.setLevel(100)
     else:
         logger.setLevel(verbose)
     logger.info("Starting isWCSIdentical: %s" %time.asctime())
-    
+
     result = True
     numsci1 = max(countext(scifile, 'SCI'), countext(scifile, 'SIPWCS'))
     numsci2 = max(countext(file2, 'SCI'), countext(file2, 'SIPWCS'))
-    
+
     if numsci1 == 0 or numsci2==0 or numsci1!= numsci2:
         logger.info("Number of SCI and SIPWCS extensions do not match.")
         result = False
-    
+
     if getRootname(scifile) != getRootname(file2):
         logger.info('Rootnames do not match.')
         result = False
@@ -60,8 +60,8 @@ def isWCSIdentical(scifile, file2, verbose=False):
     try:
         extname2 = pyfits.getval(file2, 'EXTNAME', ext=('SCI', 1))
     except KeyError:
-        extname2 = 'SIPWCS'    
-        
+        extname2 = 'SIPWCS'
+
     for i in range(1, numsci1+1):
         w1 = HSTWCS(scifile,ext=(extname1,i))
         w2 = HSTWCS(file2, ext=(extname2,i))
@@ -71,7 +71,7 @@ def isWCSIdentical(scifile, file2, verbose=False):
             not (np.array(w1.wcs.ctype) == np.array(w2.wcs.ctype)).all():
             logger.info('Primary WCSs do not match')
             result = False
-        if w1.sip or w2.sip: 
+        if w1.sip or w2.sip:
             if (w2.sip and not w1.sip) or (w1.sip and not w2.sip) or \
                 not (w1.sip.a == w2.sip.a).all() or \
                 not (w1.sip.b == w2.sip.b).all():
@@ -104,13 +104,13 @@ def isWCSIdentical(scifile, file2, verbose=False):
         if w1.vafactor != w2.vafactor:
             logger.info('VA factors do not match')
             result = False
-    
+
     return result
-        
+
 def createHeaderlet(fname, hdrname, destim=None, output=None, verbose=False):
     """
     Create a headerlet from a science observation
-    
+
     Parameters
     ----------
     fname: string
@@ -119,26 +119,27 @@ def createHeaderlet(fname, hdrname, destim=None, output=None, verbose=False):
            Name for the headerlet, stored in the primary header of the headerlet
            If output is None, hdrname is used as output
     destim: string
-           Destination image, stored in the primary header of the headerlet. 
+           Destination image, stored in the primary header of the headerlet.
            If None ROOTNAME is used of the science observation is used.
-           ROOTNAME has precedence, destim is used for observations without 
+           ROOTNAME has precedence, destim is used for observations without
             ROOTNAME in the primary header
     output: string
            Name for the headerlet file.
            HDRNAME is used if output is not given.
     verbose: False or a python logging level
-             (one of 'INFO', 'DEBUG' logging levels) 
-             (an integer representing a logging level) 
+             (one of 'INFO', 'DEBUG' logging levels)
+             (an integer representing a logging level)
     """
+
     if verbose == False:
         logger.setLevel(100)
     else:
         logger.setLevel(verbose)
     logger.info("Starting createHeaderlet: %s" %time.asctime())
     fmt="%Y-%m-%dT%H:%M:%S"
-    phdukw = {'IDCTAB': True, 
-            'NPOLFILE': True, 
-            'D2IMFILE': True} 
+    phdukw = {'IDCTAB': True,
+            'NPOLFILE': True,
+            'D2IMFILE': True}
     fobj = pyfits.open(fname)
     if destim is None:
         try:
@@ -149,75 +150,92 @@ def createHeaderlet(fname, hdrname, destim=None, output=None, verbose=False):
             raise
     if hdrname is None:
         logger.critical("Required keyword 'HDRNAME' not given")
-        raise ValueError, "Please provide a name for the headerlet, HDRNAME is a required parameter."
-    
-        
-        
+        raise ValueError("Please provide a name for the headerlet, HDRNAME is "
+                         "a required parameter.")
+
+
+
     altkeys = altwcs.wcskeys(fobj[('SCI',1)].header)
     try:
         upwcsver = fobj[0].header.ascard['STWCSVER']
     except KeyError:
-        upwcsver = pyfits.Card("STWCSVER", " ","Version of STWCS used to update the WCS")
+        upwcsver = pyfits.Card("STWCSVER", " ",
+                               "Version of STWCS used to update the WCS")
     if 'O' in altkeys:
         altkeys.remove('O')
     numsci = countext(fname, 'SCI')
-    logger.debug("Number of 'SCI' extensions in file %s is %s" % (fname, numsci))
+    logger.debug("Number of 'SCI' extensions in file %s is %s"
+                 % (fname, numsci))
     hdul = pyfits.HDUList()
     phdu = pyfits.PrimaryHDU()
-    phdu.header.update('DESTIM', destim, comment='Destination observation root name')
-    phdu.header.update('HDRNAME',hdrname, comment='Headerlet name')
-    phdu.header.update('DATE',time.strftime(fmt), comment='Date FITS file was generated')
+    phdu.header.update('DESTIM', destim,
+                       comment='Destination observation root name')
+    phdu.header.update('HDRNAME', hdrname, comment='Headerlet name')
+    phdu.header.update('DATE', time.strftime(fmt),
+                       comment='Date FITS file was generated')
     phdu.header.ascard.append(upwcsver)
-    
+
     updateRefFiles(fobj[0].header.ascard, phdu.header.ascard)
-    phdu.header.update(key='VAFACTOR', value=fobj[('SCI',1)].header.get('VAFACTOR', 1.))
+    phdu.header.update(key='VAFACTOR',
+                       value=fobj[('SCI',1)].header.get('VAFACTOR', 1.))
     hdul.append(phdu)
-    
-    for e in range(1,numsci+1):
-        hwcs = HSTWCS(fname,ext=('SCI',e))
+
+    for e in range(1, numsci+1):
+        hwcs = HSTWCS(fname,ext=('SCI', e))
         h = hwcs.wcs2header(sip2hdr=True).ascard
         for ak in altkeys:
-            awcs = HSTWCS(fname,ext=('SCI',e), wcskey=ak)
+            awcs = HSTWCS(fname,ext=('SCI', e), wcskey=ak)
             h.extend(awcs.wcs2header(idc2hdr=False).ascard)
-        h.insert(0,pyfits.Card(key='EXTNAME', value='SIPWCS', comment='Extension name'))
+        h.insert(0, pyfits.Card(key='EXTNAME', value='SIPWCS',
+                 comment='Extension name'))
         h.insert(1,pyfits.Card(key='EXTVER', value=e, comment='Extension version'))
-        
-        fhdr = fobj[('SCI',e)].header.ascard
+
+        fhdr = fobj[('SCI', e)].header.ascard
         if phdukw['NPOLFILE']:
-            
+
             cpdis = fhdr['CPDIS*...']
-            for c in range(1,len(cpdis)+1):
-                h.append(cpdis[c-1])
-                dp = fhdr['DP%s.*...'%c]
+            for c in range(1, len(cpdis) + 1):
+                h.append(cpdis[c - 1])
+                dp = fhdr['DP%s.*...' % c]
                 h.extend(dp)
-                
-                try: h.append(fhdr['CPERROR%s'%c])
-                except KeyError: pass
-                
-            try: h.append(fhdr['NPOLEXT'])
-            except KeyError: pass
-            
+
+                try:
+                    h.append(fhdr['CPERROR%s' % c])
+                except KeyError:
+                    pass
+
+            try:
+                h.append(fhdr['NPOLEXT'])
+            except KeyError:
+                pass
+
         if phdukw['D2IMFILE']:
-            try: h.append(fhdr['D2IMEXT'])
-            except KeyError: pass
-            
-            try: h.append(fhdr['AXISCORR'])
-            except KeyError: 
-                logger.exception("Required keyword AXISCORR was not found in %s['SCI',%d]" %(fname,e))
+            try:
+                h.append(fhdr['D2IMEXT'])
+            except KeyError:
+                pass
+
+            try:
+                h.append(fhdr['AXISCORR'])
+            except KeyError:
+                logger.exception("Required keyword AXISCORR was not found in "
+                                 "%s['SCI',%d]" % (fname, e))
                 raise
-            
-            try: h.append(fhdr['D2IMERR'])
-            except KeyError: h.append(pyfits.Card(key='DPERROR', value=0, 
-                                                comment='Maximum error of D2IMARR'))
-            
+
+            try:
+                h.append(fhdr['D2IMERR'])
+            except KeyError:
+                h.append(pyfits.Card(key='DPERROR', value=0,
+                                     comment='Maximum error of D2IMARR'))
+
         hdu = pyfits.ImageHDU(header=pyfits.Header(h))
         # temporary fix for pyfits ticket # 48
         hdu._extver = e
         hdul.append(hdu)
     numwdvarr = countext(fname, 'WCSDVARR')
     numd2im = countext(fname, 'D2IMARR')
-    for w in range(1, numwdvarr+1):
-        hdu = fobj[('WCSDVARR',w)].copy()
+    for w in range(1, numwdvarr + 1):
+        hdu = fobj[('WCSDVARR', w)].copy()
         # temporary fix for pyfits ticket # 48
         hdu._extver = w
         hdul.append(hdu)
@@ -229,15 +247,16 @@ def createHeaderlet(fname, hdrname, destim=None, output=None, verbose=False):
     if output is not None:
         # write the headerlet to a file
         if not output.endswith('_hdr.fits'):
-            output = output+'_hdr.fits'
-        hdul.writeto(output,clobber=True)
+            output = output + '_hdr.fits'
+        hdul.writeto(output, clobber=True)
     fobj.close()
     return Headerlet(hdul)
 
-def applyHeaderlet(hdrfile, destfile, destim=None, hdrname=None, createheaderlet=True, verbose=False):
+def applyHeaderlet(hdrfile, destfile, destim=None, hdrname=None,
+                   createheaderlet=True, verbose=False):
     """
     Apply headerlet 'hdrfile' to a science observation 'destfile'
-    
+
     Parameters
     ----------
     hdrfile: string
@@ -245,41 +264,44 @@ def applyHeaderlet(hdrfile, destfile, destim=None, hdrname=None, createheaderlet
     destfile: string
              File name of science observation wyhose WCS solution willbe updated
     destim: string or None (default)
-            ROOTNAME of destfile (default) 
-            This string will be written as the DESTIM keyword in the headerlet, 
+            ROOTNAME of destfile (default)
+            This string will be written as the DESTIM keyword in the headerlet,
             created from the old WCS solution
-            Normally it should be None, unless the science file is missing the 
-            ROOTNAME kw, in which case the name of the file (stripped of .fits) 
+            Normally it should be None, unless the science file is missing the
+            ROOTNAME kw, in which case the name of the file (stripped of .fits)
             should be specified.
     hdrname: string or None (default)
             will be the value of the HDRNAME keyword in the headerlet.
             It's not  required if createheaderlet is False
     createheaderlet: boolean
-            True (default): before updating, create a headerlet with the 
+            True (default): before updating, create a headerlet with the
             WCS old solution.
     verbose: False or a python logging level
-             (one of 'INFO', 'DEBUG' logging levels) 
-             (an integer representing a logging level)  
+             (one of 'INFO', 'DEBUG' logging levels)
+             (an integer representing a logging level)
     """
+
     logger.info("Starting applyHeaderlet: %s" %time.asctime())
     hlet = Headerlet(hdrfile)
-    hlet.apply2obs(destfile, destim=destim, hdrname=hdrname, createheaderlet=createheaderlet)
+    hlet.apply2obs(destfile, destim=destim, hdrname=hdrname,
+                   createheaderlet=createheaderlet)
 
 def updateRefFiles(source, dest):
     """
     Update the reference files name in the primary header of 'dest'
     using values from 'source'
-    
+
     Parameters
     ----------
     source: pyfits.Header.ascardlist
     dest:   pyfits.Header.ascardlist
     """
+
     logger.info("Updating reference files")
-    phdukw = {'IDCTAB': True, 
-            'NPOLFILE': True, 
-            'D2IMFILE': True} 
-    
+    phdukw = {'IDCTAB': True,
+            'NPOLFILE': True,
+            'D2IMFILE': True}
+
     try:
         wind = dest.index_of('HISTORY')
     except KeyError:
@@ -295,32 +317,37 @@ def getRootname(fname):
     """
     returns the value of ROOTNAME or DESTIM
     """
+
     try:
         rootname = pyfits.getval(fname, 'ROOTNAME')
     except KeyError:
         rootname = pyfits.getval(fname, 'DESTIM')
     return rootname
-            
+
 def mapFitsExt2HDUListInd(fname, extname):
     """
     Map FITS extensions with 'EXTNAME' to HDUList indexes.
     """
+
     if isinstance(fname, str):
         f = pyfits.open(fname)
     else:
         f = fname
     d = {}
     for hdu in f:
+        # TODO: Replace calls to header.has_key() with `in header` once
+        # pyfits refactoring branch is in production use
         if hdu.header.has_key('EXTNAME') and hdu.header['EXTNAME'] == extname:
             extver = hdu.header['EXTVER']
             d[(extname, extver)] = f.index_of((extname, extver))
     f.close()
     return d
-            
+
 def countext(fname, extname):
     """
     Return the number of extensions with EXTNAME in the file.
     """
+
     if isinstance(fname, str):
         f = pyfits.open(fname)
     else:
@@ -329,17 +356,19 @@ def countext(fname, extname):
     for hdu in f:
         if hdu.header.has_key('EXTNAME') and hdu.header['EXTNAME'] == extname:
             numext+=1
-    logger.debug("file %s has %s extensions with extname=%s" % (f.filename(), numext, extname))
+    logger.debug("file %s has %s extensions with extname=%s"
+                 % (f.filename(), numext, extname))
     return numext
 
 def _delDestWCS(dest):
     """
     Delete the WCS of a science file
     """
-    logger.info("Deleting all WCSs of file %s" %dest) 
+
+    logger.info("Deleting all WCSs of file %s" %dest)
     fobj = pyfits.open(dest, mode='update')
     numext = len(fobj)
-    
+
     for e in range(numext):
         _removeD2IM(fobj[e])
         _removeSIP(fobj[e])
@@ -348,36 +377,39 @@ def _delDestWCS(dest):
         _removeIDCCoeffs(fobj[e])
         try:
             del fobj[e].header.ascard['VAFACTOR']
-        except KeyError: pass
-        
-    _removeAltWCS(fobj, ext=range(numext)) 
-    numwdvarr = countext(dest,'WCSDVARR')
-    numd2im = countext(dest,'D2IMARR')
-    for i in range(1, numwdvarr+1):
-        del fobj[('WCSDVARR',i)]
-    for i in range(1, numd2im+1):
-        del fobj[('D2IMARR',i)]
+        except KeyError:
+            pass
+
+    _removeAltWCS(fobj, ext=range(numext))
+    numwdvarr = countext(dest, 'WCSDVARR')
+    numd2im = countext(dest, 'D2IMARR')
+    for i in range(1, numwdvarr + 1):
+        del fobj[('WCSDVARR', i)]
+    for i in range(1, numd2im + 1):
+        del fobj[('D2IMARR', i)]
     fobj.close()
-    
+
 def _removeSIP(ext):
     """
     Remove the SIP distortion of a FITS extension
     """
-    logger.debug("Removing SIP distortion from (%s, %s)" % (ext.name, ext._extver))
-    for prefix in ['A','B', 'AP', 'BP']:
-        try:   
-            order = ext.header[prefix+'_ORDER']
-            del ext.header[prefix+'_ORDER']
+
+    logger.debug("Removing SIP distortion from (%s, %s)"
+                 % (ext.name, ext._extver))
+    for prefix in ['A', 'B', 'AP', 'BP']:
+        try:
+            order = ext.header[prefix + '_ORDER']
+            del ext.header[prefix + '_ORDER']
         except KeyError:
             continue
-        for i in range(order+1):
-            for j in range(order+1):
-                key = prefix + '_%d_%d' % (i,j)
+        for i in range(order + 1):
+            for j in range(order + 1):
+                key = prefix + '_%d_%d' % (i, j)
                 try:
                     del ext.header[key]
                 except KeyError:
                     pass
-    try: 
+    try:
         del ext.header['IDCTAB']
     except KeyError:
         pass
@@ -386,15 +418,17 @@ def _removeLUT(ext):
     """
     Remove the Lookup Table distortion of a FITS extension
     """
-    logger.debug("Removing LUT distortion from (%s, %s)" % (ext.name, ext._extver))
+
+    logger.debug("Removing LUT distortion from (%s, %s)"
+                 % (ext.name, ext._extver))
     try:
         cpdis = ext.header['CPDIS*']
-    except KeyError: 
+    except KeyError:
         return
     try:
-        for c in range(1,len(cpdis)+1):
-            del ext.header['DP%s.*...'%c]
-            del ext.header[cpdis[c-1].key]   
+        for c in range(1, len(cpdis) + 1):
+            del ext.header['DP%s.*...' % c]
+            del ext.header[cpdis[c - 1].key]
         del ext.header['CPERR*']
         del ext.header['NPOLFILE']
         del ext.header['NPOLEXT']
@@ -405,21 +439,25 @@ def _removeD2IM(ext):
     """
     Remove the Detector to Image correction of a FITS extension
     """
-    logger.debug("Removing D2IM correction from (%s, %s)" % (ext.name, ext._extver))
+
+    logger.debug("Removing D2IM correction from (%s, %s)"
+                 % (ext.name, ext._extver))
     d2imkeys = ['D2IMFILE', 'AXISCORR', 'D2IMEXT', 'D2IMERR']
     for k in d2imkeys:
         try:
             del ext.header[k]
         except KeyError:
             pass
-        
+
 def _removeAltWCS(dest, ext):
     """
     Remove Alternate WCSs of a FITS extension.
     A WCS with wcskey 'O' is never deleted.
     """
-    dkeys = altwcs.wcskeys(dest[('SCI',1)].header)
-    logger.debug("Removing alternate WCSs with keys %s from %s" % (dkeys, dest.filename()))
+
+    dkeys = altwcs.wcskeys(dest[('SCI', 1)].header)
+    logger.debug("Removing alternate WCSs with keys %s from %s"
+                 % (dkeys, dest.filename()))
     for k in dkeys:
         altwcs.deleteWCS(dest, ext=ext, wcskey=k)
 
@@ -427,35 +465,42 @@ def _removePrimaryWCS(ext):
     """
     Remove the primary WCS of a FITS extension
     """
-    logger.debug("Removing Primary WCS from (%s, %s)" % (ext.name, ext._extver))
+
+    logger.debug("Removing Primary WCS from (%s, %s)"
+                 % (ext.name, ext._extver))
     naxis = ext.header.ascard['NAXIS'].value
     for key in basic_wcs:
-        for i in range(1,naxis+1):
+        for i in range(1, naxis + 1):
             try:
-                del ext.header.ascard[key+str(i)]
-            except KeyError: pass
+                del ext.header.ascard[key + str(i)]
+            except KeyError:
+                pass
     try:
         del ext.header.ascard['WCSAXES']
-    except KeyError: pass
+    except KeyError:
+        pass
 
 def _removeIDCCoeffs(ext):
     """
     Remove IDC coefficients of a FITS extension
     """
-    logger.debug("Removing IDC coefficient from (%s, %s)" % (ext.name, ext._extver))
+
+    logger.debug("Removing IDC coefficient from (%s, %s)"
+                 % (ext.name, ext._extver))
     coeffs = ['OCX10', 'OCX11', 'OCY10', 'OCY11', 'IDCSCALE']
     for k in coeffs:
         try:
             del ext.header.ascard[k]
         except KeyError:
             pass
-    
-    
+
+
 class Headerlet(HDUList):
     """
     A Headerlet class
     Ref: http://stsdas.stsci.edu/stsci_python_sphinxdocs/stwcs/headerlet_def.html
     """
+
     def __init__(self, fname, wcskeys=[], verbose=False):
         """
         Parameters
@@ -464,10 +509,11 @@ class Headerlet(HDUList):
                 Name of headerlet file
         wcskeys: python list
                 a list of wcskeys to be included in the headerlet
-                created from the old WCS solution before the 
+                created from the old WCS solution before the
                 science file is updated. If empty: all alternate (if any)
                 WCSs are copied to the headerlet.
         """
+
         logger.info("Creating a Headerlet object from wcskeys %s" % wcskeys)
         self.wcskeys = wcskeys
         if isinstance(fname,str):
@@ -475,36 +521,38 @@ class Headerlet(HDUList):
         elif isinstance(fname, list):
             fobj = fname
         else:
-            raise ValueError, "Input must be a file name (string) or a pyfits file object (HDUList)."
-        HDUList.__init__(self, fobj) 
+            raise ValueError("Input must be a file name (string) or a pyfits "
+                             "file object (HDUList).")
+        HDUList.__init__(self, fobj)
         self.fname = self.filename()
         self.hdrname = self[0].header["HDRNAME"]
-        self.stwcsver = self[0].header.get("STWCSVER","")
+        self.stwcsver = self[0].header.get("STWCSVER", "")
         self.destim = self[0].header["DESTIM"]
-        self.idctab = self[0].header.get("IDCTAB","")
-        self.npolfile = self[0].header.get("NPOLFILE","")
-        self.d2imfile = self[0].header.get("D2IMFILE","")
+        self.idctab = self[0].header.get("IDCTAB", "")
+        self.npolfile = self[0].header.get("NPOLFILE", "")
+        self.d2imfile = self[0].header.get("D2IMFILE", "")
         self.vafactor = self[1].header.get("VAFACTOR", 1) #None instead of 1?
         self.d2imerr = 0
         self.axiscorr = 1
-        
+
     def apply2obs(self,dest, destim=None, hdrname=None, createheaderlet=True):
         """
         apply this headerlet to a file
         """
+
         self.hverify()
         if self.verify_dest(dest):
             if createheaderlet:
                 createHeaderlet(dest, hdrname, destim)
             _delDestWCS(dest)
             fobj = pyfits.open(dest, mode='update')
-            
+
             updateRefFiles(self[0].header.ascard, fobj[0].header.ascard)
             numsip = countext(self, 'SIPWCS')
-            for i in range(1,numsip+1):
-                fhdr = fobj[('SCI',i)].header.ascard
-                siphdr = self[('SIPWCS',i)].header.ascard
-                # a minimal attempt to get the position of the WCS keywords group 
+            for i in range(1, numsip + 1):
+                fhdr = fobj[('SCI', i)].header.ascard
+                siphdr = self[('SIPWCS', i)].header.ascard
+                # a minimal attempt to get the position of the WCS keywords group
                 # in the header by looking for the PA_APER kw.
                 # at least make sure the WCS kw are written befir the HISTORY kw
                 # if everything fails, append the kw to the header
@@ -517,41 +565,46 @@ class Headerlet(HDUList):
                         wind = len(fhdr)
                 logger.debug("Inserting WCS keywords at index %s" % wind)
                 for k in siphdr.keys():
-                    if k not in ['XTENSION', 'BITPIX', 'NAXIS', 'PCOUNT', 
-                                 'GCOUNT','EXTNAME', 'EXTVER', 'ORIGIN', 
+                    if k not in ['XTENSION', 'BITPIX', 'NAXIS', 'PCOUNT',
+                                 'GCOUNT','EXTNAME', 'EXTVER', 'ORIGIN',
                                  'INHERIT', 'DATE', 'IRAF-TLM']:
                         fhdr.insert(wind, siphdr[k])
                     else:
                         pass
             #! Always attach these extensions last. Otherwise therr headers may
-            # get updated with the other WCS kw. 
+            # get updated with the other WCS kw.
             numwdvar = countext(self,'WCSDVARR')
             numd2im = countext(self, 'D2IMARR')
-            for e in range(1,numwdvar+1):
-                hdu = self[('WCSDVARR',e)].copy()
-                fobj.append(self[('WCSDVARR',e)].copy())
-            for e in range(1, numd2im+1):
-                fobj.append(self[('D2IMARR',e)].copy())
+            for e in range(1, numwdvar + 1):
+                hdu = self[('WCSDVARR', e)].copy()
+                fobj.append(self[('WCSDVARR', e)].copy())
+            for e in range(1, numd2im + 1):
+                fobj.append(self[('D2IMARR', e)].copy())
             fobj.close()
         else:
-            logger.critical("Observation %s cannot be updated with headerlet %s" %(dest, self.hdrname))
-            print "Observation %s cannot be updated with headerlet %s" %(dest, self.hdrname)
-        
-        
+            logger.critical("Observation %s cannot be updated with headerlet "
+                            "%s" %(dest, self.hdrname))
+            print "Observation %s cannot be updated with headerlet %s" \
+                  %(dest, self.hdrname)
+
+
     def hverify(self):
         self.verify()
-        assert(self[0].header.has_key('DESTIM') and self[0].header['DESTIM']!= " ")
-        assert(self[0].header.has_key('HDRNAME') and self[0].header['HDRNAME']!= " ")
+        assert(self[0].header.has_key('DESTIM') and
+               self[0].header['DESTIM'].strip())
+        assert(self[0].header.has_key('HDRNAME') and
+               self[0].header['HDRNAME'].strip())
         assert(self[0].header.has_key('STWCSVER'))
-        
-    
+
+
     def verify_dest(self, dest):
         """
         verifies that the headerlet can be applied to the observation
-       
-        DESTIM in the primary header of the headerlet must match ROOTNAME 
+
+        DESTIM in the primary header of the headerlet must match ROOTNAME
         of the science file (or the name of the destination file)
         """
+
         try:
             droot = pyfits.getval(dest, 'ROOTNAME')
         except KeyError:
@@ -563,8 +616,8 @@ class Headerlet(HDUList):
         else:
             logger.debug("verify_destim() returned False")
             return False
-        
+
     def tofile(self, fname, destim=None, hdrname=None, clobber=False):
         if not destim or not hdrname:
             self.hverify()
-        self.writeto(fname, clobber=clobber)
\ No newline at end of file
+        self.writeto(fname, clobber=clobber)