old_contents: """Module that allows latex output notebooks to be conditioned before
  they are converted.
  """
  #-----------------------------------------------------------------------------
  # 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 __future__ import print_function, absolute_import
  
  # Our own imports
  # Needed to override preprocessor
  from .base import (Preprocessor)
  from IPython.nbconvert import filters
  
  #-----------------------------------------------------------------------------
  # Classes
  #-----------------------------------------------------------------------------
  
  class LatexPreprocessor(Preprocessor):
      """
      Converter for latex destined documents.
      """
  
      def preprocess_cell(self, cell, resources, index):
          """
          Apply a transformation on each cell,
          
          Parameters
          ----------
          cell : NotebookNode cell
              Notebook cell being processed
          resources : dictionary
              Additional resources used in the conversion process.  Allows
              preprocessors to pass variables into the Jinja engine.
          index : int
              Modified index of the cell being processed (see base.py)
          """
          
          #If the cell is a markdown cell, preprocess the ampersands used to
          #remove the space between them and their contents.  Latex will complain
          #if spaces exist between the ampersands and the math content.  
          #See filters.latex.rm_math_space for more information.
          if hasattr(cell, "source") and cell.cell_type == "markdown":
              cell.source = filters.strip_math_space(cell.source)
          return cell, resources
  
new_contents: """Module that allows latex output notebooks to be conditioned before
  they are converted.
  """
  #-----------------------------------------------------------------------------
  # 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 __future__ import print_function, absolute_import
  
  # Third-party import, needed for Pygments latex definitions.
  from pygments.formatters import LatexFormatter
  
  # ipy imports
  from .base import (Preprocessor)
  from IPython.nbconvert import filters
  
  #-----------------------------------------------------------------------------
  # Classes
  #-----------------------------------------------------------------------------
  
  class LatexPreprocessor(Preprocessor):
      """
      Converter for latex destined documents.
      """
  
      def preprocess(self, nb, resources):
          """
          Preprocessing to apply on each notebook.
          
          Parameters
          ----------
          nb : NotebookNode
              Notebook being converted
          resources : dictionary
              Additional resources used in the conversion process.  Allows
              preprocessors to pass variables into the Jinja engine.
          """
          # Generate Pygments definitions for Latex 
          resources["pygment_definitions"] = LatexFormatter().get_style_defs()
          return super(LatexPreprocessor, self).preprocess(nb, resources)
  
  
      def preprocess_cell(self, cell, resources, index):
          """
          Apply a transformation on each cell,
          
          Parameters
          ----------
          cell : NotebookNode cell
              Notebook cell being processed
          resources : dictionary
              Additional resources used in the conversion process.  Allows
              preprocessors to pass variables into the Jinja engine.
          index : int
              Modified index of the cell being processed (see base.py)
          """
          
          #If the cell is a markdown cell, preprocess the ampersands used to
          #remove the space between them and their contents.  Latex will complain
          #if spaces exist between the ampersands and the math content.  
          #See filters.latex.rm_math_space for more information.
          if hasattr(cell, "source") and cell.cell_type == "markdown":
              cell.source = filters.strip_math_space(cell.source)
          return cell, resources
  
subject: Move the pygments definition importing logic from the sphinx preprocessor to the latex one. Now all latex templates will use pygments.