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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def normalize(rp_pyxb):
 """Normalize a ReplicationPolicy PyXB type in place. The preferred and blocked lists are sorted alphabetically. As blocked nodes override preferred nodes, and any node present in both lists is removed from the preferred list. Args: rp_pyxb : ReplicationPolicy PyXB object The object will be normalized in place. """


    # noinspection PyMissingOrEmptyDocstring
    def sort(r, a):
        d1_common.xml.sort_value_list_pyxb(_get_attr_or_list(r, a))

    rp_pyxb.preferredMemberNode = set(_get_attr_or_list(rp_pyxb, 'pref')) - set(
        _get_attr_or_list(rp_pyxb, 'block')
    )
    sort(rp_pyxb, 'block')
    sort(rp_pyxb, 'pref')