def add_handler(self, handler):
        """Adds a handler. Also checks if it is callable.
        To bypass checks, use Event.append() instead."""
        if not callable(handler):
            raise TypeError("'%s' is not callable." % handler)

        self.append(handler)
def add_handler ( self , handler ) : if not callable ( handler ) : raise TypeError ( "'%s' is not callable." % handler ) self . append ( handler )
Adds a handler. Also checks if it is callable.
        To bypass checks, use Event.append() instead.