expression : name comparison_number number
                   | name comparison_string string
                   | name comparison_equality boolean_value
                   | name comparison_equality none
                   | name comparison_in_list const_list_value

def p_expression_comparison(self, p):
        """
        expression : name comparison_number number
                   | name comparison_string string
                   | name comparison_equality boolean_value
                   | name comparison_equality none
                   | name comparison_in_list const_list_value
        """
        p[0] = Expression(left=p[1], operator=p[2], right=p[3])