docs: def p_network_sentence(self, t):
          """network_sentence : NETWORK VAR
                              | NETWORK VAR LPAREN features RPAREN"""
  
          if len(t) == 3:
              t[0] = network(t[2], reference=True, line=t.lineno(1))
          else:
              t[0] = network(t[2], t[4], line=t.lineno(1))