diff --git a/stix2/base.py b/stix2/base.py
index 7336285..910042a 100644
--- a/stix2/base.py
+++ b/stix2/base.py
@@ -537,8 +537,10 @@ _JSON_ESCAPE_MAP = {
     "f": "\f",
     "n": "\n",
     "r": "\r",
-    "t": "\t"
+    "t": "\t",
 }
+
+
 def _un_json_escape(json_string):
     """
     Removes JSON string literal escapes.  We should undo these things Python's
diff --git a/stix2/test/v21/test_deterministic_ids.py b/stix2/test/v21/test_deterministic_ids.py
index da72142..1e6e2d4 100644
--- a/stix2/test/v21/test_deterministic_ids.py
+++ b/stix2/test/v21/test_deterministic_ids.py
@@ -189,14 +189,16 @@ def test_empty_hash():
         SomeSCO(hashes={})
 
 
-@pytest.mark.parametrize("json_escaped, expected_unescaped", [
-    ("", ""),
-    ("a", "a"),
-    (r"\n", "\n"),
-    (r"\n\r\b\t\\\/\"", "\n\r\b\t\\/\""),
-    (r"\\n", r"\n"),
-    (r"\\\n", "\\\n")
-])
+@pytest.mark.parametrize(
+    "json_escaped, expected_unescaped", [
+        ("", ""),
+        ("a", "a"),
+        (r"\n", "\n"),
+        (r"\n\r\b\t\\\/\"", "\n\r\b\t\\/\""),
+        (r"\\n", r"\n"),
+        (r"\\\n", "\\\n"),
+    ],
+)
 def test_json_unescaping(json_escaped, expected_unescaped):
     actual_unescaped = stix2.base._un_json_escape(json_escaped)
     assert actual_unescaped == expected_unescaped
diff --git a/stix2/test/v21/test_observed_data.py b/stix2/test/v21/test_observed_data.py
index 8cf2389..e0fa456 100644
--- a/stix2/test/v21/test_observed_data.py
+++ b/stix2/test/v21/test_observed_data.py
@@ -1,6 +1,5 @@
 import datetime as dt
 import re
-import uuid
 
 import pytest
 import pytz