return complMultipartUpload.Parts[i].PartNumber < complMultipartUpload.Parts[j].PartNumber
	}) {
		writeErrorResponse(ctx, w, errorCodes.ToAPIErr(ErrInvalidPartOrder), r.URL)
		return
	}

	// Reject retention or governance headers if set, CompleteMultipartUpload spec
	// does not use these headers, and should not be passed down to checkPutObjectLockAllowed