code: def write_metadata(self, key, values):
          
          values = Series(values)
          self.parent.put(self._get_metadata_path(key), values, format='table',
                          encoding=self.encoding, errors=self.errors,
                          nan_rep=self.nan_rep)
docs: write out a meta data array to the key as a fixed-format Series
  
          Parameters
          ----------
          key : string
          values : ndarray