'Set the draggable state -- if state is
* None : toggle the current state
* True : turn draggable on
* False : turn draggable off
If draggable is on, you can drag the annotation on the canvas with
the mouse.  The DraggableAnnotation helper instance is returned if
draggable is on.'

def draggable(self, state=None, use_blit=False):

    from matplotlib.offsetbox import DraggableAnnotation
    is_draggable = (self._draggable is not None)
    if (state is None):
        state = (not is_draggable)
    if state:
        if (self._draggable is None):
            self._draggable = DraggableAnnotation(self, use_blit)
    else:
        if (self._draggable is not None):
            self._draggable.disconnect()
        self._draggable = None
    return self._draggable
