harvest.form.py

class MapFilterForm(forms.Form):
    form = None
    created__gte = forms.DateField(required=False)
    created__lte = forms.DateField(required=False)
    device = forms.ModelChoiceField(queryset=DeviceTeam.objects.all(),
                                    required=False)
    device__in = forms.ModelMultipleChoiceField(queryset=Device.objects.all(),
                                                required=False)

    def __init__(self, form=form, data=None, files=None, auto_id='id_%s', prefix=None,
                 initial=None, error_class=ErrorList, label_suffix=None,
                 empty_permitted=False, field_order=None):
      self.form = form
      device.queryset = DeviceTeam.objects.filter(form=form)
        .values('devices')
      device__in.queryset = DeviceTeam.objects.filter(form=form)
        .values('devices')
      
      super(MapFilterForm, self).__init__(data=None, files=None, auto_id='id_%s', prefix=None,
                 initial=None, error_class=ErrorList, label_suffix=None,
                 empty_permitted=False, field_order=None)

    def get_lookups(self):
        lookups = {}
        for k, v in self.cleaned_data.items():
            if v:
                lookups[k] = v

        return lookups