@staticmethod
def _unmarshal_relationships(pkg_reader, package, parts):
    """
        Add a relationship to the source object corresponding to each of the
        relationships in *pkg_reader* with its target_part set to the actual
        target part in *parts*.
        """
    for source_uri, srel in pkg_reader.iter_srels():
        source = package if source_uri == '/' else parts[source_uri]
        target = srel.target_ref if srel.is_external else parts[srel.
            target_partname]
        source.load_rel(srel.reltype, target, srel.rId, srel.is_external)
