old_contents: import logging
  
  from regparser.tree.depth import optional_rules
  from regparser.tree.depth.derive import derive_depths
  
  import click
  
  logger = logging.getLogger(__name__)
  
  
  @click.command()
  @click.argument('markers', type=click.STRING, required=True)
  def outline_depths(markers) -> None:
      """
      Infer an outline's structure.
      Return a list of outline depths for a given list of space-separated markers.
      """
  
      # Input is space-separated.
      marker_list = markers.split(' ')
      all_solutions = derive_depths(
          marker_list,
          [optional_rules.limit_sequence_gap(1)]
      )
      depths = {tuple(str(a.depth) for a in s) for s in all_solutions}.pop()
  
      # Expected output is space-separated.
      formatted_output = ' '.join(depths)
  
      print(formatted_output)
  
  
  if __name__ == '__main__':
      """Enable running this command directly. E.g.,
      `$ python regparser/commands/outline_depths.py`. This can save 1.5 seconds
      or more of startup time.
      """
      outline_depths()
  
new_contents: import logging
  
  from regparser.tree.depth import optional_rules
  from regparser.tree.depth.derive import derive_depths
  
  import click
  
  logger = logging.getLogger(__name__)
  
  
  @click.command()
  @click.argument('markers', type=click.STRING, required=True)
  def outline_depths(markers) -> None:
      """
      Infer an outline's structure.
      Return a list of outline depths for a given list of space-separated markers.
      """
  
      # Input is space-separated.
      marker_list = markers.split(' ')
      all_solutions = derive_depths(
          marker_list,
          [optional_rules.limit_sequence_gap(1)]
      )
      depths = {tuple(str(a.depth) for a in s) for s in all_solutions}.pop()
  
      # Expected output is space-separated.
      formatted_output = ' '.join(depths)
  
      click.echo(formatted_output)
  
  
  if __name__ == '__main__':
      """Enable running this command directly. E.g.,
      `$ python regparser/commands/outline_depths.py`. This can save 1.5 seconds
      or more of startup time.
      """
      outline_depths()
  
subject: Use click.echo() for python 2.7 compatibility