def METHOD_NAME(inputfile, wffile, sourcelanguage="en", targetlanguage=None):
    """converts a .po file (possibly many) to a Wordfast TM file"""
    inputstore = po.pofile(inputfile)
    for inunit in inputstore.units:
        if inunit.isheader() or inunit.isblank() or not inunit.istranslated():
            continue
        source = inunit.source
        target = inunit.target
        newunit = wffile.addsourceunit(source)
        newunit.target = target
        newunit.targetlang = targetlanguage