Linter fix.
Linter fix.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=286407318

GoogleCloudPlatform/PerfKitBenchmarker,GoogleCloudPlatform/PerfKitBenchmarker,GoogleCloudPlatform/PerfKitBenchmarker,GoogleCloudPlatform/PerfKitBenchmarker