code: def __get_unused_context(self, parse_result, context):
          
          tags_keys = set([t['key'] for t in parse_result['tags'] if t['from_context']])
          result_context = [c for c in context if c['key'] not in tags_keys]
          return result_context
docs: Used to get unused context from context.  Any keys not in
          parse_result
  
          Args:
              parse_results(list): parsed results used to identify what keys
                  in the context are used.
              context(list): this is the context used to match with parsed results
                  keys missing in the parsed results are the unused context
  
          Returns:
              list: A list of the unused context results.