code: def get_file_type_map():
      
      file_type_map = {}
      for strategy_type in get_strategy_types():
          for ext in strategy_type.file_types:
              if ext in file_type_map:
                  raise KeyError(
                      'File type {ext} already registered to {file_type_map[ext]}'
                      .format(**locals()))
              file_type_map[ext] = strategy_type
      return file_type_map
docs: Map file types (extensions) to strategy types.