def examples_dir( f = nil )
      if File.exists?( config_file_path )
        form_file_name( examples_dir_from_config_file, f )
      else
        form_file_name( config_dir( '/examples' ), f )
      end
    end
def examples_dir( f = nil )
      if File.exists?( config_file_path )
        form_file_name( examples_dir_from_config_file, f )
      else
        form_file_name( config_dir( '/examples' ), f )
      end
    end
returns the directory where rapidoc searches for examples