docs: def develop_unlink(options, info):
      '''
      Prepare development environment.
  
      Perform the following steps:
  
       - Unlink working ``.pioenvs`` directory into Conda ``Library`` directory.
       - Unlink ``dmf_control_board_firmware`` Python package from site packages
         directory.
  
      See Also
      --------
      :func:`develop_link`
      '''
      project_dir = ph.path(__file__).realpath().parent
  
      # Unlink working ``.pioenvs`` directory into Conda ``Library`` directory.
      info('Unlink working firmware directories from Conda environment.')
      pio_bin_dir = pioh.conda_bin_path()
      fw_bin_dir = pio_bin_dir.joinpath('dmf-control-board-firmware')
  
      if fw_bin_dir.exists():
          fw_config_ini = fw_bin_dir.joinpath('platformio.ini')
          if fw_config_ini.exists():
              fw_config_ini.unlink()
          fw_bin_dir.unlink()
  
      # Remove link to ``dmf_control_board_firmware`` Python package in
      # `conda.pth` in site packages directory.
      info('Unlink working Python directory from Conda environment...')
      ch.conda_exec('develop', '-u', project_dir, verbose=True)
      info(72 * '-' + '\nFinished')