code: def get_keyword(self, kwd, *args):
          
          try:
              kwds = self.get_header()
              return kwds[kwd]
          except KeyError:
              # return a default if there is one
              if len(args) > 0:
                  return args[0]
              raise KeyError(kwd)
docs: Get an item from the fits header, if any.