Revert in_.

Author: WaVEV

django_mongodb/lookups.py

@@ -1,6 +1,4 @@
-from django.core.exceptions import EmptyResultSet, FullResultSet
 from django.db import NotSupportedError
-from django.db.models.expressions import Value
 from django.db.models.fields.related_lookups import In, MultiColSource, RelatedIn
 from django.db.models.lookups import (
     BuiltinLookup,
@@ -50,14 +48,6 @@ def in_(self, compiler, connection):
 def is_null(self, compiler, connection):
     if not isinstance(self.rhs, bool):
         raise ValueError("The QuerySet value for an isnull lookup must be True or False.")
-    if isinstance(self.lhs, Value):
-        if self.lhs.value is None or (
-            self.lhs.value == "" and connection.features.interprets_empty_strings_as_nulls
-        ):
-            result_exception = FullResultSet if self.rhs else EmptyResultSet
-        else:
-            result_exception = EmptyResultSet if self.rhs else FullResultSet
-        raise result_exception
     lhs_mql = process_lhs(self, compiler, connection)
     return connection.mongo_operators["isnull"](lhs_mql, self.rhs)