diff --git a/setup.cfg b/setup.cfg
index 86bd85a..3851d2f 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,5 +1,5 @@
 [flake8]
-ignore = E203
+ignore = E203,W504
 max-line-length = 110
 exclude = .git,__pycache__,.eggs/,dist/,.mypy_cache
 
diff --git a/src/pycalver/version.py b/src/pycalver/version.py
index 058044f..35c6f2e 100644
--- a/src/pycalver/version.py
+++ b/src/pycalver/version.py
@@ -18,7 +18,7 @@ def current_calver() -> str:
     return dt.date.today().strftime("v%Y%m")
 
 
-def bump(old_version: str, *, release: str=None) -> str:
+def bump(old_version: str, *, release: str = None) -> str:
     # old_version is assumed to be a valid calver string,
     # validated in pycalver.config.parse.
     old_ver = parse.parse_version_info(old_version)