PyCharm 中没有 turtle 模块的提示

问题：PyCharm 中没有 turtle 模块的提示
方案：打开turtle.py文件，搜索__all__，修改其值：

__all__ = ['ScrolledCanvas', 'TurtleScreen', 'Screen', 'RawTurtle', 'Turtle', 'RawPen', 'Pen', 'Shape', 'Vec2D',
           'back','backward', 'begin_fill', 'begin_poly', 'bk', 'addshape', 'bgcolor', 'bgpic', 'bye', 'clearscreen',
         'colormode', 'delay', 'exitonclick', 'getcanvas', 'getshapes', 'listen', 'mainloop', 'mode', 'numinput',
         'onkey', 'onkeypress', 'onkeyrelease', 'onscreenclick', 'ontimer', 'register_shape', 'resetscreen',
         'screensize', 'setup', 'Terminator', 'setworldcoordinates', 'textinput', 'title', 'tracer', 'turtles',
         'update', 'window_height', 'window_width', 'write_docstringdict', 'done', 'circle', 'clear', 'clearstamp',
         'clearstamps', 'clone', 'color', 'degrees', 'distance', 'dot', 'down', 'end_fill', 'end_poly', 'fd',
         'fillcolor', 'filling', 'forward', 'get_poly', 'getpen', 'getscreen', 'get_shapepoly', 'getturtle', 'goto',
        'heading', 'hideturtle', 'home', 'ht', 'isdown', 'isvisible', 'left', 'lt', 'onclick', 'ondrag', 'onrelease',
         'pd', 'pen', 'pencolor', 'pendown', 'pensize', 'penup', 'pos', 'position', 'pu', 'radians', 'right', 'reset',
         'resizemode', 'rt', 'seth', 'setheading', 'setpos', 'setposition', 'settiltangle', 'setundobuffer', 'setx',
         'sety', 'shape', 'shapesize', 'shapetransform', 'shearfactor', 'showturtle', 'speed', 'st', 'stamp', 'tilt',
         'tiltangle', 'towards', 'turtlesize', 'undo', 'undobufferentries', 'up', 'width', 'write', 'xcor', 'ycor']