python’s sum() and non-integer values

Its a bit tricky – the sum() function takes the start and adds it to the next and so on

You need to implement the __radd__ method:

class T:
    def __init__(self,x):
        self.x = x
    def __radd__(self, other):
        return other + self.x

test = (T(1),T(2),T(3),200)
print sum(test)