[pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

lib/iris/__init__.py

@@ -143,6 +143,7 @@ def callback(cube, field, filename):
 #: To be used when copying a cube to make the new cube dataless.
 DATALESS = "NONE"
 
+
 class Future(threading.local):
     """Run-time configuration controller."""