GeoDjango lookups must be accept F() input

[Mohammad Hasanzadeh]

For example, if we need to calculate the distance between two field of the model with the distance_gte lookup like the following:

return queryset.filter(checkin_position__distance_gte=(F("doctor_location__location__position"),  D(km=200)) )

We will get the following error:
ValueError: Cannot use object with type F for a spatial lookup parameter.

Note that doctor_location__location__position is a PointField.