':param  selector:   some partial string in the desired tags to return
:param  max_depth:  the number of generations of descendents to return'

def __init__(self, source, selector=None, max_depth=None, **kwargs):

    self.selector = selector
    self.max_depth = max_depth
    self.namespaces = {}
    super(XMLDataProvider, self).__init__(source, **kwargs)
