'Compute .mo name from .po name or language'

def make_filenames(self, filename, outfile=None):

    if filename.endswith('.po'):
        infile = filename
    else:
        infile = (filename + '.po')
    if (outfile is None):
        outfile = (os.path.splitext(infile)[0] + '.mo')
    return (infile, outfile)
