code: def _getStrandType(self, strand):
          
  
          # TODO make this a dictionary/enum:  PLUS, MINUS, BOTH, UNKNOWN
          strand_id = None
          if strand == '+':
              strand_id = self.globaltt['plus_strand']
          elif strand == '-':
              strand_id = self.globaltt['minus_strand']
          elif strand == '.':
              strand_id = self.globaltt['both_strand']
          elif strand is None:  # assume this is Unknown
              pass
          else:
              LOG.warning("strand type could not be mapped: %s", str(strand))
  
          return strand_id
docs: :param strand:
          :return: