old_contents: import exceptions
  
  class BaseCacheModule(object):
  
      def get(self, key):
          raise exceptions.NotImplementedError
  
      def set(self, key, value):
          raise exceptions.NotImplementedError
  
      def keys(self):
          raise exceptions.NotImplementedError
  
      def contains(self, key):
          raise exceptions.NotImplementedError
  
      def delete(self, key):
          raise exceptions.NotImplementedError
  
      def flush(self):
          raise exceptions.NotImplementedError
  
new_contents: # (c) 2014, Brian Coca, Josh Drake, et al
  #
  # This file is part of Ansible
  #
  # Ansible is free software: you can redistribute it and/or modify
  # it under the terms of the GNU General Public License as published by
  # the Free Software Foundation, either version 3 of the License, or
  # (at your option) any later version.
  #
  # Ansible is distributed in the hope that it will be useful,
  # but WITHOUT ANY WARRANTY; without even the implied warranty of
  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  # GNU General Public License for more details.
  #
  # You should have received a copy of the GNU General Public License
  # along with Ansible.  If not, see <http://www.gnu.org/licenses/>.
  
  import exceptions
  
  class BaseCacheModule(object):
  
      def get(self, key):
          raise exceptions.NotImplementedError
  
      def set(self, key, value):
          raise exceptions.NotImplementedError
  
      def keys(self):
          raise exceptions.NotImplementedError
  
      def contains(self, key):
          raise exceptions.NotImplementedError
  
      def delete(self, key):
          raise exceptions.NotImplementedError
  
      def flush(self):
          raise exceptions.NotImplementedError
  
subject: Add copyright header, let me know if corrections are needed.