'Sets allowed values'

def __init__(self, user, skip=None, *args, **kwargs):

    if (skip is None):
        skip = []
    super(FilterForm, self).__init__(*args, **kwargs)
    if ('caller' in skip):
        del self.fields['caller']
    else:
        self.fields['caller'].queryset = Object.filter_permitted(user, Contact.objects, mode='x')
        self.fields['caller'].widget.attrs.update({'class': 'autocomplete', 'callback': reverse('identities_ajax_contact_lookup')})
        self.fields['caller'].label = _('Caller')
    if ('status' in skip):
        del self.fields['status']
    else:
        self.fields['status'].queryset = Object.filter_permitted(user, TicketStatus.objects, mode='x')
        self.fields['status'].label = _('Status')
    self.fields['service'].queryset = Object.filter_permitted(user, Service.objects, mode='x')
    self.fields['service'].label = _('Service')
    self.fields['sla'].queryset = Object.filter_permitted(user, ServiceLevelAgreement.objects, mode='x')
    self.fields['sla'].label = _('SLA')
    if ('queue' in skip):
        del self.fields['queue']
    else:
        self.fields['queue'].queryset = Object.filter_permitted(user, TicketQueue.objects, mode='x')
        self.fields['queue'].label = _('Queue')
    if ('assigned' in skip):
        del self.fields['assigned']
    else:
        self.fields['assigned'].queryset = Object.filter_permitted(user, ServiceAgent.objects, mode='x')
        self.fields['assigned'].widget.attrs.update({'class': 'multicomplete', 'callback': reverse('services_ajax_agent_lookup')})
        self.fields['assigned'].label = _('Assigned    to')
        self.fields['assigned'].help_text = ''
