'Connect two bboxes with a straight line.
Parameters
bbox1, bbox2 : `matplotlib.transforms.Bbox`
Bounding boxes to connect.
loc1 : {1, 2, 3, 4}
Corner of *bbox1* to draw the line. Valid values are::
\'upper right\'  : 1,
\'upper left\'   : 2,
\'lower left\'   : 3,
\'lower right\'  : 4
loc2 : {1, 2, 3, 4}, optional
Corner of *bbox2* to draw the line. If None, defaults to *loc1*.
Valid values are::
\'upper right\'  : 1,
\'upper left\'   : 2,
\'lower left\'   : 3,
\'lower right\'  : 4
**kwargs
Patch properties for the line drawn. Valid arguments include:
%(Patch)s'

@docstring.dedent_interpd
def __init__(self, bbox1, bbox2, loc1, loc2=None, **kwargs):

    if (u'transform' in kwargs):
        raise ValueError(u'transform    should    not    be    set')
    kwargs[u'transform'] = IdentityTransform()
    Patch.__init__(self, fill=False, **kwargs)
    self.bbox1 = bbox1
    self.bbox2 = bbox2
    self.loc1 = loc1
    self.loc2 = loc2
