Return |_SerializedRelationships| instance loaded with the
        relationships contained in *rels_item_xml*. Returns an empty
        collection if *rels_item_xml* is |None|.

def load_from_xml(baseURI, rels_item_xml):
        """
        Return |_SerializedRelationships| instance loaded with the
        relationships contained in *rels_item_xml*. Returns an empty
        collection if *rels_item_xml* is |None|.
        """
        srels = _SerializedRelationships()
        if rels_item_xml is not None:
            rels_elm = parse_xml(rels_item_xml)
            for rel_elm in rels_elm.Relationship_lst:
                srels._srels.append(_SerializedRelationship(baseURI, rel_elm))
        return srels