Functors are objects that can be called like a function. They are typically used as callback functions. And they typically remember some value making the act as a closure.
#!/usr/bin/env python class doSomethingWithAnInt(object): def __init__( self, i): self.i = i def __call__( self): print( "frozen ", self.i) a = doSomethingWithAnInt(3) a()