def __init__(self):
    super(NoGceContainerDeclarationMetadataKey, self).__init__("Instance doesn't have {} metadata key - it is not a container.".format(GCE_CONTAINER_DECLARATION))
def __init__(self):
    super(NoGceContainerDeclarationMetadataKey, self).__init__("Instance doesn't have {} metadata key - it is not a container.".format(GCE_CONTAINER_DECLARATION))