from types import MethodType, FunctionType


class Foo(object):
    def __init__(self):
        self.name = "MyName"

    def func(self):
        print(self.name)


obj = Foo()
print(isinstance(obj.func, FunctionType))  # False
print(isinstance(obj.func, MethodType))  # True   #说明这是一个方法

print(isinstance(Foo.func, FunctionType))  # True   #说明这是一个函数。
print(isinstance(Foo.func, MethodType))  # False

print(type(obj.func)) # <class 'method'>
print(type(Foo.func)) # <class 'function'>

REF

https://www.zhihu.com/question/317390856/answer/632194800