@classmethod
def parse_csv(cls, fn, sep=';'):
    """ Grammar retro-ingennired from manufacturing.csv """
    cls.log.debug('opening file: %s' % fn)
    cpt = 0
    for line in open(fn):
        if cpt == 0:
            cpt += 1
            continue
        v1, v2 = line.strip().split(sep)[0:2]
        w = 1
        yield int(v1), int(v2), w, None
