diff --git a/src/fideslang/default_fixtures.py b/src/fideslang/default_fixtures.py
index 9838a83..c8f9a4b 100644
--- a/src/fideslang/default_fixtures.py
+++ b/src/fideslang/default_fixtures.py
@@ -9,7 +9,6 @@
 2. Copy/Paste the JSON response below
 """
 
-
 COUNTRY_CODES = [
     {"name": "Afghanistan", "alpha3Code": "AFG"},
     {"name": "Åland Islands", "alpha3Code": "ALA"},
diff --git a/src/fideslang/default_taxonomy/__init__.py b/src/fideslang/default_taxonomy/__init__.py
index b032904..6b16070 100644
--- a/src/fideslang/default_taxonomy/__init__.py
+++ b/src/fideslang/default_taxonomy/__init__.py
@@ -7,8 +7,8 @@
 from .data_uses import DEFAULT_DATA_USES
 from .organizations import DEFAULT_ORGANIZATIONS
 
-sort_data_types = (
-    lambda x: x.parent_key if hasattr(x, "parent_key") and x.parent_key else x.fides_key
+sort_data_types = lambda x: (
+    x.parent_key if hasattr(x, "parent_key") and x.parent_key else x.fides_key
 )
 
 DEFAULT_TAXONOMY = Taxonomy(
diff --git a/src/fideslang/manifests.py b/src/fideslang/manifests.py
index 60143a0..8868ffc 100644
--- a/src/fideslang/manifests.py
+++ b/src/fideslang/manifests.py
@@ -1,4 +1,5 @@
 """This module handles anything related to working with raw manifest files."""
+
 import glob
 from functools import reduce
 from typing import Dict, List, Set, Union
diff --git a/src/fideslang/models.py b/src/fideslang/models.py
index 03e2979..2310dfa 100644
--- a/src/fideslang/models.py
+++ b/src/fideslang/models.py
@@ -470,7 +470,7 @@ def valid_meta(cls, meta_values: Optional[FidesMeta]) -> Optional[FidesMeta]:
                 "The 'return_all_elements' attribute can only be specified on array fields."
             )
         return meta_values
-    
+
     @model_validator(mode="after")
     def validate_object_fields(
         self,
@@ -493,6 +493,8 @@ def validate_object_fields(
                     f"The data type '{data_type}' on field '{field_name}' is not compatible with specified sub-fields. Convert to an 'object' field."
                 )
 
+        return self
+
 
 # this is required for the recursive reference in the pydantic model:
 DatasetField.model_rebuild()
diff --git a/src/fideslang/parse.py b/src/fideslang/parse.py
index 9c1a25c..27d04fd 100644
--- a/src/fideslang/parse.py
+++ b/src/fideslang/parse.py
@@ -2,6 +2,7 @@
 This module handles everything related to parsing resources into Pydantic models,
 either from local files or the server.
 """
+
 from typing import Dict, List
 
 from fideslang import FidesModel, Taxonomy, model_map
diff --git a/src/fideslang/validation.py b/src/fideslang/validation.py
index 9c1639c..74c3c46 100644
--- a/src/fideslang/validation.py
+++ b/src/fideslang/validation.py
@@ -1,6 +1,7 @@
 """
 Contains all of the additional validation for the resource models.
 """
+
 import re
 from collections import Counter
 from typing import Annotated, Dict, List, Optional, Pattern, Set, Tuple
diff --git a/tests/fideslang/test_validation.py b/tests/fideslang/test_validation.py
index 21f3174..f7fe122 100644
--- a/tests/fideslang/test_validation.py
+++ b/tests/fideslang/test_validation.py
@@ -717,21 +717,26 @@ def test_return_all_elements_on_array_field(self):
         )
 
     def test_data_categories_at_object_level(self):
-        # Data categories at the object level ARE allowed now
-        DatasetField(
+
+        field = DatasetField(
             name="test_field",
             data_categories=["user"],
             fides_meta=FidesMeta(
                 references=None,
-                identity=None,
+                identify=None,
                 primary_key=False,
                 data_type="object",
                 length=None,
                 return_all_elements=None,
                 read_only=None,
-            )
+            ),
+            fields=[DatasetField(name="nested_field")],
         )
 
+        assert field
+        assert field.data_categories == ["user"]
+        assert field.fides_meta.data_type == "object"
+
     def test_data_categories_on_nested_fields(self):
 
         field = DatasetField(
@@ -756,17 +761,15 @@ def test_data_categories_on_nested_fields(self):
                         primary_key=False,
                         data_type="string",
                         length=None,
-                        return_all_elements=None,
                         read_only=None,
+                        data_categories=["user"],
                     ),
                 )
             ],
         )
 
         assert field
-        assert field.fields
-        print(f"fields: {field.fields}")
-        print(f"field:  {vars(field)}")
+        assert field.data_categories == ["user"]
         assert field.fields[0].data_categories == ["user"]