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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 pyxb_to_dict(rp_pyxb):
 """Convert ReplicationPolicy PyXB object to a normalized dict. Args: rp_pyxb: ReplicationPolicy to convert. Returns: dict : Replication Policy as normalized dict. Example:: { 'allowed': True, 'num': 3, 'blockedMemberNode': {'urn:node:NODE1', 'urn:node:NODE2', 'urn:node:NODE3'}, 'preferredMemberNode': {'urn:node:NODE4', 'urn:node:NODE5'}, } """

    return {
        'allowed': bool(_get_attr_or_list(rp_pyxb, 'allowed')),
        'num': _get_as_int(rp_pyxb),
        'block': _get_as_set(rp_pyxb, 'block'),
        'pref': _get_as_set(rp_pyxb, 'pref'),
    }