'Return a generator of artists that can be used as handles in
a legend.'

def _get_legend_handles(self, legend_handler_map=None):

    handles_original = (((self.lines + self.patches) + self.collections) + self.containers)
    handler_map = mlegend.Legend.get_default_handler_map()
    if (legend_handler_map is not None):
        handler_map = handler_map.copy()
        handler_map.update(legend_handler_map)
    has_handler = mlegend.Legend.get_legend_handler
    for handle in handles_original:
        label = handle.get_label()
        if ((label != u'_nolegend_') and has_handler(handler_map, handle)):
            (yield handle)
