Why calling method for two times result in TypeError: object is not callable-CodePudding

Define two class based on BaseHandler as below:

class BaseHandler:
    def successor(self, successor):
        self.successor = successor

class ScoreHandler1(BaseHandler):
    pass

class ScoreHandler2(BaseHandler):
    pass

Initialize two instances:

h1 = ScoreHandler1()
h2 = ScoreHandler2()

Call successor method first time :

h1.successor(h2)

Now call it second time:

h1.successor(h2)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'ScoreHandler2' object is not callable

Why can't call the method more times?

callable(ScoreHandler2)
True

CodePudding user response：

The first time you call h1.successor(h2), you're calling the method named "successor". Inside this method, you set the attribute named "successor" to the object h2.

The second time you call h1.successor(h2), you're calling the attribute named "successor", which you defined previously to h2. Since ScoreHandler2 does not implement __call__, it'll raise an error.

To fix this, avoid naming attributes with the same name as methods.