old_contents: 
  ##  Central class for reading and writing meshes.
  #
  #   This class is created by Application and handles reading and writing mesh files.
  class MeshFileHandler(object):
      def __init__(self):
          self._mesh_readers = []
          self._mesh_writers = []
      
      # Try to read the mesh_data from a file. Based on the extension in the file a correct meshreader is selected.
      # \param file_name The name of the mesh to load.
      # \param storage_device The StorageDevice where the mesh can be found.
      # \returns MeshData if it was able to read the file, None otherwise.
      def read(self, file_name, storage_device):
          try:
              for reader in self._mesh_readers:
                  result = reader.read(file_name, storage_device)
                  if(result is not None):
                      return result
  
          except OSError as e:
              print(e)
  
          return None #unable to read
      
      # Try to write the mesh_data to file. Based on the extension in the file_name a correct meshwriter is selected.
      # \param file_name The name of the file to write.
      # \param storage_device The StorageDevice where the file should be written to.
      # \param mesh_data
      # \returns True if it was able to create the file, otherwise False
      def write(self, file_name, storage_location, mesh_data):
          if(mesh_data is None):
              return False
          for writer in self._mesh_writers:
              if(writer.write(storage_location, mesh_data)):
                  return True
          return False
      
      # Get list of all supported filetypes for writing.
      # \returns List of strings with all supported filetypes.
      def getSupportedFileTypesWrite(self):
          supported_types = []
          for writer in self._mesh_writer:
              supported_types.append(writer.getSupportedExtension())
          return supported_types
      
      # Get list of all supported filetypes for reading.
      # \returns List of strings with all supported filetypes.
      def getSupportedFileTypesRead(self):
          supported_types = []
          for reader in self._mesh_readers:
              supported_types.append(reader.getSupportedExtension())
          return supported_types
          
      def addWriter(self, writer):
          self._mesh_writers.append(writer)
          
      def addReader(self, reader):
          self._mesh_readers.append(reader)
  
new_contents: from Cura.Logger import Logger
  
  ##  Central class for reading and writing meshes.
  #
  #   This class is created by Application and handles reading and writing mesh files.
  class MeshFileHandler(object):
      def __init__(self):
          self._mesh_readers = []
          self._mesh_writers = []
      
      # Try to read the mesh_data from a file. Based on the extension in the file a correct meshreader is selected.
      # \param file_name The name of the mesh to load.
      # \param storage_device The StorageDevice where the mesh can be found.
      # \returns MeshData if it was able to read the file, None otherwise.
      def read(self, file_name, storage_device):
          try:
              for reader in self._mesh_readers:
                  result = reader.read(file_name, storage_device)
                  if(result is not None):
                      return result
  
          except OSError as e:
              Logger.log("e", e)
  
          Logger.log("w", "Unable to read file %s", file_name)
          return None #unable to read
      
      # Try to write the mesh_data to file. Based on the extension in the file_name a correct meshwriter is selected.
      # \param file_name The name of the file to write.
      # \param storage_device The StorageDevice where the file should be written to.
      # \param mesh_data
      # \returns True if it was able to create the file, otherwise False
      def write(self, file_name, storage_location, mesh_data):
          if(mesh_data is None):
              return False
          for writer in self._mesh_writers:
              if(writer.write(storage_location, mesh_data)):
                  return True
          return False
      
      # Get list of all supported filetypes for writing.
      # \returns List of strings with all supported filetypes.
      def getSupportedFileTypesWrite(self):
          supported_types = []
          for writer in self._mesh_writer:
              supported_types.append(writer.getSupportedExtension())
          return supported_types
      
      # Get list of all supported filetypes for reading.
      # \returns List of strings with all supported filetypes.
      def getSupportedFileTypesRead(self):
          supported_types = []
          for reader in self._mesh_readers:
              supported_types.append(reader.getSupportedExtension())
          return supported_types
          
      def addWriter(self, writer):
          self._mesh_writers.append(writer)
          
      def addReader(self, reader):
          self._mesh_readers.append(reader)
  
subject: Add some logging to MeshFileHandler