Update formatting in Python tests using the current version of Black.

Author: adamreichold

examples/simple/tests/test_ext.py

@@ -1,11 +1,19 @@
 import numpy as np
-from rust_ext import head, axpy, conj, mult, extract, add_minutes_to_seconds, polymorphic_add
+from rust_ext import (
+    head,
+    axpy,
+    conj,
+    mult,
+    extract,
+    add_minutes_to_seconds,
+    polymorphic_add,
+)
 
 
 def test_head():
-    x = np.array(['first', None, 42])
+    x = np.array(["first", None, 42])
     first = head(x)
-    assert first == 'first'
+    assert first == "first"
 
 
 def test_axpy():