def read_rels(archive):
    """Read relationships for a workbook"""
    xml_source = archive.read(ARC_WORKBOOK_RELS)
    tree = fromstring(xml_source)
    for element in safe_iterator(tree, '{%s}Relationship' % PKG_REL_NS):
        rId = element.get('Id')
        pth = element.get("Target")
        typ = element.get('Type')
        # normalise path
        if pth.startswith("/xl"):
            pth = pth.replace("/xl", "xl")
        elif not pth.startswith("xl") and not pth.startswith(".."):
            pth = "xl/" + pth
        yield rId, {'path':pth, 'type':typ}
Read relationships for a workbook