'Onaccept callback for work assignments
@param form: the FORM'

@classmethod
def assignment_onaccept(cls, form):

    try:
        formvars = form.vars
    except AttributeError:
        return
    db = current.db
    atable = current.s3db.work_assignment
    if ('job_id' not in formvars):
        if ('id' not in formvars):
            return
        record_id = formvars.id
        row = db((atable.id == record_id)).select(atable.job_id, limitby=(0, 1)).first()
        if (not row):
            return
        job_id = row.job_id
    else:
        job_id = formvars.job_id
    if job_id:
        cls.update_workers_assigned(job_id)
    return
