'Get whether to skip (filter-out) the specified attribute.
@param attr: An attribute.
@type attr: I{Attribute}
@return: True if should be skipped.
@rtype: bool'

def skip(self, attr):

    ns = attr.namespace()
    skip = (Namespace.xmlns[1], 'http://schemas.xmlsoap.org/soap/encoding/', 'http://schemas.xmlsoap.org/soap/envelope/', 'http://www.w3.org/2003/05/soap-envelope')
    return (Namespace.xs(ns) or (ns[1] in skip))
