code: def p_arglist(p):
      '''
      arglist : arg
              | arglist COMMA arg
      '''
      if len(p) == 2:
          p[0] = [p[1]]
      else:
          p[0] = p[1]
          p[0].append(p[3]f p_arglist(p):
      '''
      arglist : arg
              | arglist COMMA arg
      '''
      if len(p) == 2:
          p[0] = [p[1]]
      else:
          p[0] = p[1]
          p[0].append(p[3])
docs: arglist : arg
              | arglist COMMA arg