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`

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')