While a lambda is still processing (archive unpacking etc), the lambda state should be set to "Pending" (currently "Active") and invocations to that lambda should fail (currently, it can end up in a inconsistent state in this case, like lambdas being executed without layers).

Lambda state should reflect the current internal state, and invocations should fail if not active.
region = LambdaRegion.get()
    try:
        region.code_signing_configs.pop(arn)
    except KeyError:
        msg = "The Lambda code signing configuration %s can not be found." % (arn)
        return not_found_error(msg)
    return Response("", status=204)
@app.route("/2020-04-22/code-signing-configs/<arn>", methods=["PUT"])
def update_code_signing_config(arn):