old_contents: """Global configuration class."""
  #-----------------------------------------------------------------------------
  # Copyright (c) 2013, the IPython Development Team.
  #
  # Distributed under the terms of the Modified BSD License.
  #
  # The full license is in the file COPYING.txt, distributed with this software.
  #-----------------------------------------------------------------------------
  
  #-----------------------------------------------------------------------------
  # Imports
  #-----------------------------------------------------------------------------
  
  from IPython.utils.traitlets import List
  from IPython.config.configurable import LoggingConfigurable
  from IPython.utils.traitlets import Unicode
  
  #-----------------------------------------------------------------------------
  # Classes and functions
  #-----------------------------------------------------------------------------
             
  class NbConvertBase(LoggingConfigurable):
      """Global configurable class for shared config
  
      Useful for display data priority that might be use by many transformers
      """
  
      display_data_priority = List(['html', 'javascript', 'application/pdf', 'svg', 'latex', 'png', 'jpg', 'jpeg' , 'text'],
              config=True,
                help= """
                      An ordered list of preferred output type, the first
                      encountered will usually be used when converting discarding
                      the others.
                      """
              )
  
      default_language = Unicode('ipython', config=True, help='default highlight language')
  
      def __init__(self, **kw):
          super(NbConvertBase, self).__init__(**kw)
  
new_contents: """Global configuration class."""
  #-----------------------------------------------------------------------------
  # Copyright (c) 2013, the IPython Development Team.
  #
  # Distributed under the terms of the Modified BSD License.
  #
  # The full license is in the file COPYING.txt, distributed with this software.
  #-----------------------------------------------------------------------------
  
  #-----------------------------------------------------------------------------
  # Imports
  #-----------------------------------------------------------------------------
  
  from IPython.utils.traitlets import List
  from IPython.config.configurable import LoggingConfigurable
  from IPython.utils.traitlets import Unicode
  
  #-----------------------------------------------------------------------------
  # Classes and functions
  #-----------------------------------------------------------------------------
             
  class NbConvertBase(LoggingConfigurable):
      """Global configurable class for shared config
  
      Useful for display data priority that might be use by many transformers
      """
  
      display_data_priority = List(['html', 'application/pdf', 'svg', 'latex', 'png', 'jpg', 'jpeg' , 'text'],
              config=True,
                help= """
                      An ordered list of preferred output type, the first
                      encountered will usually be used when converting discarding
                      the others.
                      """
              )
  
      default_language = Unicode('ipython', config=True, help='default highlight language')
  
      def __init__(self, **kw):
          super(NbConvertBase, self).__init__(**kw)
  
subject: Revert "Add Javascript to display priority of base nbconvert class."