code: def p_cmp_expression(tok):
          
          if len(tok) == 4:
              tok[0] = ComparisonBinOpRule(tok[2], tok[1], tok[3])
          else:
              tok[0] = tok[1]
docs: cmp_expression : term OP_LIKE cmp_expression
                            | term OP_IN cmp_expression
                            | term OP_IS cmp_expression
                            | term OP_EQ cmp_expression
                            | term OP_NE cmp_expression
                            | term OP_GT cmp_expression
                            | term OP_GE cmp_expression
                            | term OP_LT cmp_expression
                            | term OP_LE cmp_expression
                            | term