diff --git a/src/waitress/adjustments.py b/src/waitress/adjustments.py
index fbbd024b..e8ebb752 100644
--- a/src/waitress/adjustments.py
+++ b/src/waitress/adjustments.py
@@ -505,7 +505,9 @@ def parse_args(cls, argv):
             try:
                 kw["app"] = pkgutil.resolve_name(app)
             except (ValueError, ImportError, AttributeError) as exc:
-                raise AppResolutionError(f"Cannot import WSGI application '{app}': {exc}")
+                raise AppResolutionError(
+                    f"Cannot import WSGI application '{app}': {exc}",
+                )
             if kw["call"]:
                 kw["app"] = kw["app"]()