Simulate click within window screen.

        Args:
            x, y: int, pixel distance from window (left, top) as origin

        Returns:
            None

def click(self, x, y):
        """Simulate click within window screen.

        Args:
            x, y: int, pixel distance from window (left, top) as origin

        Returns:
            None
        """
        print 'click at', x, y
        self._input_left_mouse(x, y)