'Sets allowed values'

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

    if (skip is None):
        skip = []
    super(SLAFilterForm, self).__init__(*args, **kwargs)
    self.fields['client'].queryset = Object.filter_permitted(user, Contact.objects, mode='x')
    self.fields['client'].required = False
    self.fields['client'].widget.attrs.update({'class': 'autocomplete', 'callback': reverse('identities_ajax_contact_lookup')})
    self.fields['client'].label = _('Client')
    self.fields['provider'].queryset = Object.filter_permitted(user, Contact.objects, mode='x')
    self.fields['provider'].required = False
    self.fields['provider'].widget.attrs.update({'class': 'autocomplete', 'callback': reverse('identities_ajax_contact_lookup')})
    self.fields['provider'].label = _('Provider')
    self.fields['service'].queryset = Object.filter_permitted(user, Service.objects, mode='x')
    self.fields['service'].required = False
    self.fields['service'].label = _('Service')
