import abc

import six


@six.add_metaclass(abc.ABCMeta)
class BaseBackend(object):

    @abc.abstractmethod
    def setup_instance(self):
        """Called by setUpClass to setup an instance"""

    @abc.abstractmethod
    def cleanup(self):
        """Needs to cleanup the resources created in ``setup_instance``"""

@@ -1,12 +1,651 @@
+# Copyright 2015 Cloudbase Solutions Srl%0A# All Rights Reserved.%0A#%0A#    Licensed under the Apache License, Version 2.0 (the %22License%22); you may%0A#    not use this file except in compliance with the License. You may obtain%0A#    a copy of the License at%0A#%0A#         http://www.apache.org/licenses/LICENSE-2.0%0A#%0A#    Unless required by applicable law or agreed to in writing, software%0A#    distributed under the License is distributed on an %22AS IS%22 BASIS, WITHOUT%0A#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the%0A#    License for the specific language governing permissions and limitations%0A#    under the License.%0A%0A
 import abc%0A%0A

Add the license header where it's missing.