(self, fun, key=None)
Bind fun to key-press event of key if key is given,
        or to any key-press-event if no key is given.

        Arguments:
        fun -- a function with no arguments
        key -- a string: key (e.g. "a") or key-symbol (e.g. "space")

        In order to be able to register key-events, TurtleScreen
        must have focus. (See method listen.)

        Example (for a TurtleScreen instance named screen
        and a Turtle instance named turtle):

        >>> def f():
        ...     fd(50)
        ...     lt(60)
        ...
        >>> screen.onkeypress(f, "Up")
        >>> screen.listen()

        Subsequently the turtle can be moved by repeatedly pressing
        the up-arrow key, or by keeping pressed the up-arrow key.
        consequently drawing a hexagon.
Bind fun to key-press event of key if key is given,
        or to any key-press-event if no key is given.
Bind fun to key - press event of key if key is given or to any key - press - event if no key is given .
def onkeypress(self, fun, key=None):
        """Bind fun to key-press event of key if key is given,
        or to any key-press-event if no key is given.

        Arguments:
        fun -- a function with no arguments
        key -- a string: key (e.g. "a") or key-symbol (e.g. "space")

        In order to be able to register key-events, TurtleScreen
        must have focus. (See method listen.)

        Example (for a TurtleScreen instance named screen
        and a Turtle instance named turtle):

        >>> def f():
        ...     fd(50)
        ...     lt(60)
        ...
        >>> screen.onkeypress(f, "Up")
        >>> screen.listen()

        Subsequently the turtle can be moved by repeatedly pressing
        the up-arrow key, or by keeping pressed the up-arrow key.
        consequently drawing a hexagon.
        """
        if fun is None:
            if key in self._keys:
                self._keys.remove(key)
        elif key is not None and key not in self._keys:
            self._keys.append(key)
        self._onkeypress(fun, key)
def onkeypress ( self , fun , key = None ) : if fun is None : if key in self . _keys : self . _keys . remove ( key ) elif key is not None and key not in self . _keys : self . _keys . append ( key ) self . _onkeypress ( fun , key )