add get_lookup method

Author: WaVEV

django_mongodb_backend/fields/embedded_model_array.py

@@ -12,6 +12,8 @@
 
 
 class EmbeddedModelArrayField(ArrayField):
+    ALLOWED_LOOKUPS = {"exact", "len", "overlap"}
+
     def __init__(self, embedded_model, **kwargs):
         if "size" in kwargs:
             raise ValueError("EmbeddedModelArrayField does not support size.")
@@ -57,6 +59,9 @@ def get_transform(self, name):
             return transform
         return KeyTransformFactory(name, self)
 
+    def get_lookup(self, name):
+        return super().get_lookup(name) if name in self.ALLOWED_LOOKUPS else None
+
 
 class EMFArrayRHSMixin:
     def process_rhs(self, compiler, connection):