如何让一个免费的monad解释器递归？

# 定义解释函数
def interpret(statement, environment):
    if statement.type == 'non_recursive':
        return statement.value
    elif statement.type == 'recursive':
        return recursive_call(statement, environment)

# 定义递归函数
def recursive_call(statement, environment):
    if statement.condition:
        # 更新环境变量
        new_environment = update_environment(statement, environment)
        # 递归调用
        return interpret(statement.recursive_statement, new_environment)
    else:
        # 终止递归
        return statement.value

# 测试解释器
environment = {}
statement = NonRecursiveStatement('non_recursive', 'Hello World')
result = interpret(statement, environment)
print(result)  # 输出：Hello World

recursive_statement = RecursiveStatement('recursive', 'Hello', True)
statement = NonRecursiveStatement('non_recursive', recursive_statement)
result = interpret(statement, environment)
print(result)  # 输出：Hello