diff --git a/django_mongodb_backend/aggregates.py b/django_mongodb_backend/aggregates.py
index 31f4b29ba..798c75d6d 100644
--- a/django_mongodb_backend/aggregates.py
+++ b/django_mongodb_backend/aggregates.py
@@ -8,14 +8,7 @@
 MONGO_AGGREGATIONS = {Count: "sum"}
 
 
-def aggregate(
-    self,
-    compiler,
-    connection,
-    operator=None,
-    resolve_inner_expression=False,
-    **extra_context,  # noqa: ARG001
-):
+def aggregate(self, compiler, connection, operator=None, resolve_inner_expression=False):
     if self.filter:
         node = self.copy()
         node.filter = None
@@ -31,7 +24,7 @@ def aggregate(
     return {f"${operator}": lhs_mql}
 
 
-def count(self, compiler, connection, resolve_inner_expression=False, **extra_context):  # noqa: ARG001
+def count(self, compiler, connection, resolve_inner_expression=False):
     """
     When resolve_inner_expression=True, return the MQL that resolves as a
     value. This is used to count different elements, so the inner values are
@@ -64,12 +57,12 @@ def count(self, compiler, connection, resolve_inner_expression=False, **extra_co
     return {"$add": [{"$size": lhs_mql}, exits_null]}
 
 
-def stddev_variance(self, compiler, connection, **extra_context):
+def stddev_variance(self, compiler, connection):
     if self.function.endswith("_SAMP"):
         operator = "stdDevSamp"
     elif self.function.endswith("_POP"):
         operator = "stdDevPop"
-    return aggregate(self, compiler, connection, operator=operator, **extra_context)
+    return aggregate(self, compiler, connection, operator=operator)
 
 
 def register_aggregates():
diff --git a/django_mongodb_backend/fields/embedded_model_array.py b/django_mongodb_backend/fields/embedded_model_array.py
index a220969cd..38f119524 100644
--- a/django_mongodb_backend/fields/embedded_model_array.py
+++ b/django_mongodb_backend/fields/embedded_model_array.py
@@ -227,13 +227,14 @@ class EmbeddedModelArrayFieldLessThanOrEqual(
 
 class EmbeddedModelArrayFieldTransform(Transform):
     field_class_name = "EmbeddedModelArrayField"
+    VIRTUAL_COLUMN_ITERABLE = "item"
 
     def __init__(self, field, *args, **kwargs):
         super().__init__(*args, **kwargs)
         # Lookups iterate over the array of embedded models. A virtual column
         # of the queried field's type represents each element.
         column_target = field.clone()
-        column_name = f"$item.{field.column}"
+        column_name = f"${self.VIRTUAL_COLUMN_ITERABLE}.{field.column}"
         column_target.db_column = column_name
         column_target.set_attributes_from_name(column_name)
         self._lhs = Col(None, column_target)
@@ -283,7 +284,7 @@ def as_mql(self, compiler, connection):
                 {
                     "$map": {
                         "input": lhs_mql,
-                        "as": "item",
+                        "as": self.VIRTUAL_COLUMN_ITERABLE,
                         "in": inner_lhs_mql,
                     }
                 },
diff --git a/django_mongodb_backend/fields/polymorphic_embedded_model_array.py b/django_mongodb_backend/fields/polymorphic_embedded_model_array.py
index 6325ca4fc..c3832675a 100644
--- a/django_mongodb_backend/fields/polymorphic_embedded_model_array.py
+++ b/django_mongodb_backend/fields/polymorphic_embedded_model_array.py
@@ -98,7 +98,7 @@ def __init__(self, field, *args, **kwargs):
         # Lookups iterate over the array of embedded models. A virtual column
         # of the queried field's type represents each element.
         column_target = field.clone()
-        column_name = f"$item.{field.column}"
+        column_name = f"${self.VIRTUAL_COLUMN_ITERABLE}.{field.column}"
         column_target.name = f"{field.name}"
         column_target.db_column = column_name
         column_target.set_attributes_from_name(column_name)