style: use Black everywhere (#2594)

* style: use Black everywhere

* style: minor touchup from review

tests/test_exceptions.py

@@ -54,27 +54,27 @@ def test_python_alreadyset_in_destructor(monkeypatch, capsys):
     hooked = False
     triggered = [False]  # mutable, so Python 2.7 closure can modify it
 
-    if hasattr(sys, 'unraisablehook'):  # Python 3.8+
+    if hasattr(sys, "unraisablehook"):  # Python 3.8+
         hooked = True
         default_hook = sys.unraisablehook
 
         def hook(unraisable_hook_args):
             exc_type, exc_value, exc_tb, err_msg, obj = unraisable_hook_args
-            if obj == 'already_set demo':
+            if obj == "already_set demo":
                 triggered[0] = True
             default_hook(unraisable_hook_args)
             return
 
         # Use monkeypatch so pytest can apply and remove the patch as appropriate
-        monkeypatch.setattr(sys, 'unraisablehook', hook)
+        monkeypatch.setattr(sys, "unraisablehook", hook)
 
-    assert m.python_alreadyset_in_destructor('already_set demo') is True
+    assert m.python_alreadyset_in_destructor("already_set demo") is True
     if hooked:
         assert triggered[0] is True
 
     _, captured_stderr = capsys.readouterr()
     # Error message is different in Python 2 and 3, check for words that appear in both
-    assert 'ignored' in captured_stderr and 'already_set demo' in captured_stderr
+    assert "ignored" in captured_stderr and "already_set demo" in captured_stderr
 
 
 def test_exception_matches():
@@ -107,7 +107,9 @@ def test_custom(msg):
     # Can we fall-through to the default handler?
     with pytest.raises(RuntimeError) as excinfo:
         m.throws_logic_error()
-    assert msg(excinfo.value) == "this error should fall through to the standard handler"
+    assert (
+        msg(excinfo.value) == "this error should fall through to the standard handler"
+    )
 
     # OverFlow error translation.
     with pytest.raises(OverflowError) as excinfo:
@@ -166,7 +168,13 @@ def test_nested_throws(capture):
     # C++ -> Python -> C++ -> Python
     with capture:
         m.try_catch(
-            m.MyException5, pycatch, m.MyException, m.try_catch, m.MyException, throw_myex5)
+            m.MyException5,
+            pycatch,
+            m.MyException,
+            m.try_catch,
+            m.MyException,
+            throw_myex5,
+        )
     assert str(capture).startswith("MyException5: nested error 5")
 
     # C++ -> Python -> C++
@@ -182,7 +190,6 @@ def test_nested_throws(capture):
 
 # This can often happen if you wrap a pybind11 class in a Python wrapper
 def test_invalid_repr():
-
     class MyRepr(object):
         def __repr__(self):
             raise AttributeError("Example error")