diff --git a/tf_quant_finance/__init__.py b/tf_quant_finance/__init__.py
index 9be999d33..b438ca0b7 100644
--- a/tf_quant_finance/__init__.py
+++ b/tf_quant_finance/__init__.py
@@ -28,7 +28,7 @@
 
 
 # Ensure Python 3 is used.
-def _check_py_version():
+def _check_py_version() -> None:
   if sys.version_info[0] < 3:
     raise Exception("Please use Python 3. Python 2 is not supported.")
 
@@ -36,7 +36,7 @@ def _check_py_version():
 # Ensure TensorFlow is importable and its version is sufficiently recent. This
 # needs to happen before anything else, since the imports below will try to
 # import tensorflow, too.
-def _ensure_tf_install():  # pylint: disable=g-statement-before-imports
+def _ensure_tf_install() -> None:  # pylint: disable=g-statement-before-imports
   """Attempt to import tensorflow, and ensure its version is sufficient.
 
   Raises:
diff --git a/tf_quant_finance/utils/dataclass.py b/tf_quant_finance/utils/dataclass.py
index e5949dcbd..e516bf4ef 100644
--- a/tf_quant_finance/utils/dataclass.py
+++ b/tf_quant_finance/utils/dataclass.py
@@ -76,13 +76,13 @@ class are treated as ordered in the same order as they appear in the class
   cls = attr.s(cls, auto_attribs=True)
 
   # Define __iter__ and __len__ method to ensure tf.while_loop compatibility
-  def __iter__(self):  # pylint: disable=invalid-name
+  def __iter__(self) -> None:  # pylint: disable=invalid-name
     # Note that self.__attrs_attrs__ is a tuple so the iteration order is fixed
     for item in self.__attrs_attrs__:
       name = item.name
       yield getattr(self, name)
 
-  def __len__(self):  # pylint: disable=invalid-name
+  def __len__(self) -> int:  # pylint: disable=invalid-name
     return len(self.__attrs_attrs__)
 
   cls.__len__ = __len__
diff --git a/tf_quant_finance/utils/dataclass_test.py b/tf_quant_finance/utils/dataclass_test.py
index c60e5fb2a..09a8c9cd6 100644
--- a/tf_quant_finance/utils/dataclass_test.py
+++ b/tf_quant_finance/utils/dataclass_test.py
@@ -14,6 +14,7 @@
 # limitations under the License.
 """Tests for the Coord decorator."""
 
+from typing import Tuple
 import tensorflow.compat.v2 as tf
 
 import tf_quant_finance as tff
@@ -31,9 +32,9 @@ class Coords:
 
     @tf.function
     def fn(start_coords: Coords) -> Coords:
-      def cond(it, _):
+      def cond(it, _) -> bool:
         return it < 10
-      def body(it, coords):
+      def body(it, coords) -> Tuple(int, Coords):
         return it + 1, Coords(x=coords.x + 1, y=coords.y + 2)
       return tf.while_loop(cond, body, loop_vars=(0, start_coords))[1]
 
@@ -47,7 +48,7 @@ def body(it, coords):
     with self.subTest('SecondValue'):
       self.assertEqual(end_coords_eval.y, 20)
 
-  def test_docstring_preservation(self):
+  def test_docstring_preservation(self) -> None:
     @tff.utils.dataclass
     class Coords:
       """A coordinate grid."""
diff --git a/tf_quant_finance/utils/tf_functions_test.py b/tf_quant_finance/utils/tf_functions_test.py
index fd39d0f9f..6e626094b 100644
--- a/tf_quant_finance/utils/tf_functions_test.py
+++ b/tf_quant_finance/utils/tf_functions_test.py
@@ -19,7 +19,6 @@
 import tensorflow.compat.v2 as tf
 
 import tf_quant_finance as tff
-from tensorflow.python.framework import test_util  # pylint: disable=g-direct-tensorflow-import
 
 
 @dataclasses.dataclass
@@ -33,7 +32,7 @@ class TfFunctionsTest(tf.test.TestCase):
   def _assert_keys_values(self,
                           iterator,
                           expected_keys=None,
-                          expected_values=None):
+                          expected_values=None) -> None:
     key_lists, values = zip(*list(iterator))
     keys = ['_'.join(k) for k in key_lists]
     if expected_keys is not None and expected_values is not None:
@@ -49,33 +48,33 @@ def _assert_keys_values(self,
     if expected_values is not None:
       self.assertSameElements(values, expected_values)
 
-  def test_non_nested(self):
+  def test_non_nested(self) -> None:
     d = {'a': 1, 'b': 2}
     iterator = tff.utils.iterate_nested(d)
     self._assert_keys_values(
         iterator, expected_keys=['a', 'b'], expected_values=[1, 2])
 
-  def test_empty(self):
+  def test_empty(self) -> None:
     items = []
     for item in tff.utils.iterate_nested({}):
       items.append(item)
     self.assertEmpty(items)
 
-  def test_array_values(self):
+  def test_array_values(self) -> None:
     d = {'a': [1, 2, 3], 'b': {'c': [4, 5]}}
     self._assert_keys_values(
         tff.utils.iterate_nested(d),
         expected_keys=['a', 'b_c'],
         expected_values=[[1, 2, 3], [4, 5]])
 
-  def test_nested(self):
+  def test_nested(self) -> None:
     nested_dict = {'a': 1, 'b': [2, 3, 4], 'c': {'d': 8}}
     self._assert_keys_values(
         tff.utils.iterate_nested(nested_dict),
         expected_keys=['a', 'b', 'c_d'],
         expected_values=[1, [2, 3, 4], 8])
 
-  def test_dataclass(self):
+  def test_dataclass(self) -> None:
     d = {
         'a': {
             'b': {