如何在python RPLY中解析换行符

import rply

lexer = rply.LexerGenerator()

lexer.add('NEWLINE', r'\n')

# 定义数字的规则
lexer.add('NUMBER', r'\d+')

# 定义标识符的规则
lexer.add('IDENTIFIER', r'[a-zA-Z_][a-zA-Z0-9_]*')

# 定义运算符的规则
lexer.add('PLUS', r'\+')
lexer.add('MINUS', r'-')
lexer.add('MULTIPLY', r'\*')
lexer.add('DIVIDE', r'/')

# 忽略空格和制表符
lexer.ignore(r'\s+')

lexer = lexer.build()

from rply import ParserGenerator

# 创建ParserGenerator
pg = ParserGenerator(
    # 设置解析规则的名称和优先级
    ['NUMBER', 'PLUS', 'MINUS', 'MULTIPLY', 'DIVIDE', 'NEWLINE', 'IDENTIFIER'],
    precedence=[
        ('left', ['PLUS', 'MINUS']),
        ('left', ['MULTIPLY', 'DIVIDE'])
    ]
)

# 定义解析规则，例如一个简单的四则运算表达式
@pg.production('expression : NUMBER')
def expression_number(p):
    return int(p[0].getstr())

@pg.production('expression : expression PLUS expression')
@pg.production('expression : expression MINUS expression')
@pg.production('expression : expression MULTIPLY expression')
@pg.production('expression : expression DIVIDE expression')
def expression_operation(p):
    left = p[0]
    right = p[2]
    operator = p[1].getstr()
    if operator == '+':
        return left + right
    elif operator == '-':
        return left - right
    elif operator == '*':
        return left * right
    elif operator == '/':
        return left / right

# 语法错误处理
@pg.error
def error_handler(token):
    raise ValueError("Ran into a %s where it wasn't expected" % token.gettokentype())

# 构建解析器
parser = pg.build()

# 假设要解析的代码字符串为source_code
tokens = lexer.lex(source_code)
result = parser.parse(tokens)

pip install rply