code: def getHeader(self,exten=None):
          
          _image=fileutil.openImage(self._filename, clobber=False, memmap=False)
          _header=fileutil.getExtn(_image,extn=exten).header
          _image.close()
          del _image
          return _header
docs: Return just the specified header extension fileutil
              is used instead of fits to account for non-FITS
              input images. openImage returns a fits object.