code: def nma_attribute(self, stmt, p_elem, pset=None):
          
          att = "nma:" + stmt.keyword
          if att not in p_elem.attr:
              p_elem.attr[att] = stmt.arg
docs: Map `stmt` to a NETMOD-specific attribute.
  
          The name of the attribute is the same as the 'keyword' of
          `stmt`.