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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def wait_for_keys(self, *keys, timeout=0):
 """Waits until one of the specified keys was pressed, and returns which key was pressed. :param keys: iterable of integers of pygame-keycodes, or simply multiple keys passed via multiple arguments :type keys: iterable :param timeout: number of seconds to wait till the function returns :type timeout: float :returns: The keycode of the pressed key, or None in case of timeout :rtype: int """

        if len(keys) == 1 and _is_iterable(keys[0]):
            keys = keys[0]

        return self.listen_until_return(Handler.key_press(keys), timeout=timeout)