Fix TypeError in merge_traces tool
Fix TypeError in merge_traces tool

Bug: chromium:1302243
Change-Id: I9880e556f3403e5d309cf1baa32c50d3e7dff218
Reviewed-on: https://chromium-review.googlesource.com/c/catapult/+/3500168
Reviewed-by: John Chen <334fbfbb4df7c78f091ea1b77c69ca6ac731a3f3@chromium.org>
Reviewed-by: Erik Chen <b51d12b71fa2f8cb17021720ad5ee62fe09eb9e9@chromium.org>
Commit-Queue: Dave Tapuska <dadf7498a22f920d244afdebc30a6c098ba5e518@chromium.org>
Reviewed-by: Dave Tapuska <dadf7498a22f920d244afdebc30a6c098ba5e518@chromium.org>

catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult