I want to write custom filter with drop down field using admin_searchable_dropdown

I tried two ways too implement this and got error both times
first:
the custom filter

class PrimaryLabelFilter(AutocompleteFilter):
    field_name = 'primary_label'
    title = 'primary_label'

in the admin using it like this

    list_filter = (
        PrimaryLabelFilter,
    )

the error

Forbidden (Permission denied): /admin/autocomplete/
model_admin = self.admin_site._registry[remote_model]
              ~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^
KeyError: <class 'panel.backend.ad.models.label.Label'>

HTTP GET /admin/autocomplete/?app_label=ad&model_name=ad&field_name=primary_label 403 [0.01, 127.0.0.1:52324]

second:
in admin class

list_filter = (
        ('primary_label', PrimaryLabelFilter),
    )

the error

<class 'panel.backend.ad.admin.ad.AdAdmin'>: (admin.E115) The value of 'list_filter[0][1]' must inherit from 'FieldListFilter'.