code: def p_For(p):
      '''
      For : FOR Expression IN Expression COLON Terminator Block
          | FOR Expression COMMA Expression IN Expression COLON Terminator Block
      '''
      if len(p) <= 8:
          p[0] = For(p[2], None, p[4], p[6], p[7])
      else:
          p[0] = For(p[2], p[4], p[6], p[8], p[9]f p_For(p):
      '''
      For : FOR Expression IN Expression COLON Terminator Block
          | FOR Expression COMMA Expression IN Expression COLON Terminator Block
      '''
      if len(p) <= 8:
          p[0] = For(p[2], None, p[4], p[6], p[7])
      else:
          p[0] = For(p[2], p[4], p[6], p[8], p[9])
docs: For : FOR Expression IN Expression COLON Terminator Block
          | FOR Expression COMMA Expression IN Expression COLON Terminator Block