docstr: Generates logical filenames by appending input data filenames
  with preprocessor_string. These strings will accumulate over
  multiple preprocessors
docstr_tok: ["Generates","logical","filenames","by","appending","input","data","filenames","with","preprocessor_string",".","These","strings","will","accumulate","over","multiple","preprocessors"]
code: def generate_output_filenames(
      self, data_collection, data_group, file_extension=".nii.gz"
  ):
      """Generates logical filenames by appending input data filenames
      with preprocessor_string. These strings will accumulate over
      multiple preprocessors
      """
  
      self.output_filenames = []
  
      if data_group.source == "hdf5":
          for channel_num in range(
              data_group.data[data_collection.current_case].shape[-1]
          ):
              self.output_filenames += [
                  self.generate_output_filename(
                      "_".join(
                          [
                              data_group.label,
                              str(data_collection.current_case),
                              str(channel_num),
                          ]
                      )
                      + file_extension,
                      file_extension=file_extension,
                  )
              ]
  
      else:
          for file_idx, filename in enumerate(
              data_group.data[data_collection.current_case]
          ):
              self.output_filenames += [
                  self.generate_output_filename(
                      filename, file_extension=file_extension
                  )
              ]
  
      return
  
imports: import os
  import numpy
  from deepneuro.utilities.util import add_parameter, replace_suffix, cli_sanitize, docker_print
  from deepneuro.utilities.conversion import read_image_files, save_data
label_desc: Use image node_id 7 for calling the Preprocessor obj's underlying member method code with example usage: obj.generate_output_filenames(data_collection, data_group, file_extension) without return types