old_contents: """
  Python exporter which exports Notebook code into a PY file.
  """
  #-----------------------------------------------------------------------------
  # 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 Unicode
  
  from .templateexporter import TemplateExporter
  
  #-----------------------------------------------------------------------------
  # Classes
  #-----------------------------------------------------------------------------
  
  class PythonExporter(TemplateExporter):
      """
      Exports a Python code file.
      """
      
      file_extension = Unicode(
          'py', config=True, 
          help="Extension of the file that should be written to disk")
  
new_contents: """Python script Exporter 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 Unicode
  
  from .templateexporter import TemplateExporter
  
  #-----------------------------------------------------------------------------
  # Classes
  #-----------------------------------------------------------------------------
  
  class PythonExporter(TemplateExporter):
      """
      Exports a Python code file.
      """
      
      file_extension = Unicode(
          'py', config=True, 
          help="Extension of the file that should be written to disk")
  
      def _raw_format_default(self):
          return 'python'
      
      def _raw_formats_default(self):
          return ['py', 'python']
  
  
subject: add raw_format to Exporter classes