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")
Sets allowed values
dataset/ETHPy150Open treeio/treeio/treeio/services/forms.py/SLAFilterForm.__init__