Question

Im just playing around with decorators in python and enjoying the experience, to me a decorator class seems cleaner to me than decorator functions so I have been playing with this design

def returns(object):
    """Enforces return to a specific type"""
    def __init__(self, returns):
        self.returns = returns

    def __call__(self, func):
        def wrapped(*args):
            out = func(*args)
            return self.returns(out)
        return wrapped

@returns(int) 
def test():
    return '4'

Problem with the above code is that it returns

------------------------------------------------------------
Traceback (most recent call last):
  File "", line 1, in <module>
  File "", line 122, in runfile
    execfile(filename, glbs)
  File "", line 33, in <module>
    @returns(int)
TypeError: 'NoneType' object is not callable

Im wondering why I can call int() like a function, and it has a callable method but it says this here as its NoneType and not callable.

Any ideas?

EDIT: Please no more answers the problem has been solved and I understand what I was doing wrong. Its a typo and im defining a function not a class

Answer 1

Your returns() function returns nothing. Did you mean to make it a class?