diff --git a/lms/djangoapps/instructor/tests/test_api.py b/lms/djangoapps/instructor/tests/test_api.py
index 00b0fc56b05f..0cb7e009454e 100644
--- a/lms/djangoapps/instructor/tests/test_api.py
+++ b/lms/djangoapps/instructor/tests/test_api.py
@@ -713,7 +713,7 @@ def test_bad_file_upload_type(self):
         """
         Try uploading some non-CSV file and verify that it is rejected
         """
-        uploaded_file = SimpleUploadedFile("temp.csv", io.BytesIO(b"some initial binary data: \x00\x01").read())
+        uploaded_file = SimpleUploadedFile("temp.csv", io.BytesIO(b"some initial binary data: \xC3\x01").read())
         response = self.client.post(self.url, {'students_list': uploaded_file})
         assert response.status_code == 200
         data = json.loads(response.content.decode('utf-8'))
@@ -920,15 +920,16 @@ def test_users_created_and_enrolled_successfully_if_others_fail(self):
         manual_enrollments = ManualEnrollmentAudit.objects.all()
         assert manual_enrollments.count() == 2
 
-    @patch('lms.djangoapps.instructor.views.api', 'generate_random_string',
-           Mock(side_effect=['first', 'first', 'second']))
     def test_generate_unique_password_no_reuse(self):
         """
         generate_unique_password should generate a unique password string that hasn't been generated before.
         """
-        generated_password = ['first']
-        password = generate_unique_password(generated_password, 12)
-        assert password != 'first'
+        with patch('lms.djangoapps.instructor.views.api.generate_random_string') as mock:
+            mock.side_effect = ['first', 'first', 'second']
+
+            generated_password = ['first']
+            password = generate_unique_password(generated_password, 12)
+            assert password != 'first'
 
     @patch.dict(settings.FEATURES, {'ALLOW_AUTOMATED_SIGNUPS': False})
     def test_allow_automated_signups_flag_not_set(self):
diff --git a/lms/djangoapps/instructor/tests/test_certificates.py b/lms/djangoapps/instructor/tests/test_certificates.py
index 9921ae6d6831..ce3433f312d8 100644
--- a/lms/djangoapps/instructor/tests/test_certificates.py
+++ b/lms/djangoapps/instructor/tests/test_certificates.py
@@ -888,7 +888,7 @@ def test_bad_file_upload_type(self):
         """
         Try uploading CSV file with invalid binary data and verify that it is rejected
         """
-        uploaded_file = SimpleUploadedFile("temp.csv", io.BytesIO(b"some initial binary data: \x00\x01").read())
+        uploaded_file = SimpleUploadedFile("temp.csv", io.BytesIO(b"some initial binary data: \xC3\x01").read())
         response = self.client.post(self.url, {'students_list': uploaded_file})
         assert response.status_code == 200
         data = json.loads(response.content.decode('utf-8'))
diff --git a/openedx/core/lib/cache_utils.py b/openedx/core/lib/cache_utils.py
index 1b3b65f378a4..c379ab2d961a 100644
--- a/openedx/core/lib/cache_utils.py
+++ b/openedx/core/lib/cache_utils.py
@@ -126,7 +126,7 @@ def __init__(self, func):
         self.cache = {}
 
     def __call__(self, *args):
-        if not isinstance(args, collections.Hashable):
+        if not isinstance(args, collections.abc.Hashable):
             # uncacheable. a list, for instance.
             # better to not cache than blow up.
             return self.func(*args)
@@ -147,7 +147,10 @@ def __get__(self, obj, objtype):
         """
         Support instance methods.
         """
-        return functools.partial(self.__call__, obj)
+        partial = functools.partial(self.__call__, obj)
+        # Make the cache accessible on the wrapped object so it can be cleared if needed.
+        partial.cache = self.cache
+        return partial
 
 
 class CacheInvalidationManager:
diff --git a/xmodule/library_content_block.py b/xmodule/library_content_block.py
index 4edcca5f00b6..6c8965186d51 100644
--- a/xmodule/library_content_block.py
+++ b/xmodule/library_content_block.py
@@ -221,7 +221,7 @@ def make_selection(cls, selected, children, max_count, mode):
         overlimit_block_keys = set()
         if len(selected_keys) > max_count:
             num_to_remove = len(selected_keys) - max_count
-            overlimit_block_keys = set(rand.sample(selected_keys, num_to_remove))
+            overlimit_block_keys = set(rand.sample(list(selected_keys), num_to_remove))
             selected_keys -= overlimit_block_keys
 
         # Do we have enough blocks now?
@@ -233,7 +233,7 @@ def make_selection(cls, selected, children, max_count, mode):
             pool = valid_block_keys - selected_keys
             if mode == "random":
                 num_to_add = min(len(pool), num_to_add)
-                added_block_keys = set(rand.sample(pool, num_to_add))
+                added_block_keys = set(rand.sample(list(pool), num_to_add))
                 # We now have the correct n random children to show for this user.
             else:
                 raise NotImplementedError("Unsupported mode.")
diff --git a/xmodule/tests/xml/factories.py b/xmodule/tests/xml/factories.py
index 23a57898b6dc..a62f7b3f49bb 100644
--- a/xmodule/tests/xml/factories.py
+++ b/xmodule/tests/xml/factories.py
@@ -57,7 +57,7 @@ def __repr__(self):
 
 # Extract all argument names used to construct XmlImportData objects,
 # so that the factory doesn't treat them as XML attributes
-XML_IMPORT_ARGS = inspect.getargspec(XmlImportData.__init__).args  # lint-amnesty, pylint: disable=deprecated-method
+XML_IMPORT_ARGS = inspect.getfullargspec(XmlImportData.__init__).args
 
 
 class XmlImportFactory(Factory):