simplify contains

Author: timgraham

django_mongodb/fields/array.py

@@ -245,18 +245,7 @@ class ArrayContains(ArrayRHSMixin, FieldGetDbPrepValueMixin, Lookup):
     def as_mql(self, compiler, connection):
         lhs_mql = process_lhs(self, compiler, connection)
         value = process_rhs(self, compiler, connection)
-        return {
-            "$eq": [
-                {
-                    "$cond": {
-                        "if": {"$eq": [lhs_mql, None]},
-                        "then": False,
-                        "else": {"$setIsSubset": [value, lhs_mql]},
-                    }
-                },
-                True,
-            ]
-        }
+        return {"$and": [{"$ne": [lhs_mql, None]}, {"$setIsSubset": [value, lhs_mql]}]}
 
 
 @ArrayField.register_lookup