'*bbox*: a child :class:`Bbox`
*transform*: a 2D :class:`Transform`'

def __init__(self, bbox, transform, **kwargs):

    if (not bbox.is_bbox):
        raise ValueError(u"'bbox'    is    not    a    bbox")
    if (not isinstance(transform, Transform)):
        msg = u"'transform'    must    be    an    instance    of    'matplotlib.transform.Transform'"
        raise ValueError(msg)
    if ((transform.input_dims != 2) or (transform.output_dims != 2)):
        msg = u"The    input    and    output    dimensions    of    'transform'    must    be    2"
        raise ValueError(msg)
    BboxBase.__init__(self, **kwargs)
    self._bbox = bbox
    self._transform = transform
    self.set_children(bbox, transform)
    self._points = None
