api: Lint fixes.

Fix line-too-long and docstring-section-indent errors.

BUG=b:233893248
TEST=cros lint

Change-Id: Ieeff951187b2c7c0e371ef18cab97f31c03d81cd
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/4190795
Commit-Queue: Jack Rosenthal <jrosenth@chromium.org>
Tested-by: Alex Klein <saklein@chromium.org>
Reviewed-by: Jack Rosenthal <jrosenth@chromium.org>
Auto-Submit: Alex Klein <saklein@chromium.org>
diff --git a/api/message_util.py b/api/message_util.py
index db8bcf2..be4d294 100644
--- a/api/message_util.py
+++ b/api/message_util.py
@@ -33,10 +33,6 @@
     """Base error class for the module."""
 
 
-class InvalidHandlerError(Error):
-    """Raised when a message handler has no input/output argument when needed."""
-
-
 class InvalidInputFileError(Error):
     """Raised when the input file cannot be read."""
 
@@ -160,9 +156,9 @@
 
     The class is fairly tightly coupled to the build api, but we currently have
     no other projected use cases for this, so it's handy. In particular, if we
-    scrap the "maintain the same input/output/config serialization when reexecing
-    inside the chroot" convention, this implementation is much less useful and
-    can be fairly trivially generalized.
+    scrap the "maintain the same input/output/config serialization when
+    reexecing inside the chroot" convention, this implementation is much less
+    useful and can be fairly trivially generalized.
 
     The instance's path is the primary path the message handler was built for.
     For the Build API, this means one of the input/output/config arguments. In
@@ -252,7 +248,8 @@
             path: An optional override of the instance's path.
 
         Raises:
-            InvalidOutputFileError: When no path given, or it cannot be written to.
+            InvalidOutputFileError: When no path given, or the path cannot be
+                written to.
         """
         if not path and not self.path:
             raise InvalidOutputFileError("No output file has been specified.")