'The HandlerPatch class optionally takes a function ``patch_func``
who\'s responsibility is to create the legend key artist. The
``patch_func`` should have the signature::
def patch_func(legend=legend, orig_handle=orig_handle,
xdescent=xdescent, ydescent=ydescent,
width=width, height=height, fontsize=fontsize)
Subsequently the created artist will have its ``update_prop`` method
called and the appropriate transform will be applied.'

def __init__(self, patch_func=None, **kw):

    HandlerBase.__init__(self, **kw)
    self._patch_func = patch_func
