如何在Python中列出我自己定义的所有变量，不包括导入的变量？

import types

def get_user_defined_variables():
    variables = {}
    all_names = dir()
    for name in all_names:
        obj = getattr(__main__, name)
        if isinstance(obj, types.ModuleType):
            continue
        if isinstance(obj, types.FunctionType):
            continue
        if isinstance(obj, types.TypeType):
            continue
        variables[name] = obj
    return variables

# 调用函数获取自己定义的所有变量
user_defined_variables = get_user_defined_variables()

# 打印结果
for name, value in user_defined_variables.items():
    print(name, "=", value)