code: def p_NsContentNameList(p):
      '''
      NsContentNameList : NsContentName
                        | NsContentNameList COMMA NsContentName
      '''
      if len(p) == 2:
          p[0] = NsContentNameList(None, p[1])
      else:
          p[0] = NsContentNameList(p[1], p[3]f p_NsContentNameList(p):
      '''
      NsContentNameList : NsContentName
                        | NsContentNameList COMMA NsContentName
      '''
      if len(p) == 2:
          p[0] = NsContentNameList(None, p[1])
      else:
          p[0] = NsContentNameList(p[1], p[3])
docs: NsContentNameList : NsContentName
                        | NsContentNameList COMMA NsContentName