pename

        Set turtle shape to shape with given name or, if name is not given,
        return name of current shape.
        Shape with name must exist in the TurtleScreen's shape dictionary.
        Initially there are the following polygon shapes:
        'arrow', 'turtle', 'circle', 'square', 'triangle', 'classic'.
        To learn about how to deal with shapes see Screen-method register_shape.

        Example (for a Turtle instance named turtle):
        >>> turtle.shape()
        'arrow'
        >>> turtle.shape("turtle")
        >>> turtle.shape()
        'turtle'
        Nz