text: #
  #   Copyright 2013-2021 [The Foundry Visionmongers Ltd]
  #
  #   Licensed under the Apache License, Version 2.0 (the "License");
  #   you may not use this file except in compliance with the License.
  #   You may obtain a copy of the License at
  #
  #       http://www.apache.org/licenses/LICENSE-2.0
  #
  #   Unless required by applicable law or agreed to in writing, software
  #   distributed under the License is distributed on an "AS IS" BASIS,
  #   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  #   See the License for the specific language governing permissions and
  #   limitations under the License.
  #
  
  class PluginSystemPlugin(object):
  
      @classmethod
      def identifier(cls):
          """
          This method is required by all plugins, in order to uniquely
          identify this plugin. If there are duplicate plugins with the
          same identifier, the first one encountered will be used, and all
          others will be ignored.
          """
          raise NotImplementedError
  