how to call back a method in python3?

[水静流深]

I want to call back a function which is the method of a class .

    def callback(self.do,x):
        return(self.do(x))

That is what i want to write,when i input 
     
    def callback(self.do,x):

error message:


      File "<stdin>", line 1
        def callback(self.do,x):
                     ^
    SyntaxError: invalid syntax


`do` is a method in my class ,how to write the code?‍
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