'Update form validation
@param form: the FORM'

def validate(self, form):

    T = current.T
    formvars = form.vars
    errors = form.errors
    if (str(formvars.current_status) == '2'):
        errors.current_status = T('Bulk    update    from    this    status    not    allowed')
    if (str(formvars.new_status) == '2'):
        errors.new_status = T('Bulk    update    to    this    status    not    allowed')
    from_date = formvars.from_date
    to_date = formvars.to_date
    if (from_date and to_date and (from_date > to_date)):
        errors.to_date = T('Date    until    must    be    after    date    from')
