Returns a list of interface numbers from the output tshark -D. Used
    internally to capture on multiple interfaces.

def get_tshark_interfaces(tshark_path=None):
    """
    Returns a list of interface numbers from the output tshark -D. Used
    internally to capture on multiple interfaces.
    """
    parameters = [get_process_path(tshark_path), '-D']
    with open(os.devnull, 'w') as null:
        tshark_interfaces = subprocess.check_output(parameters, stderr=null).decode("utf-8")

    return [line.split('.')[0] for line in tshark_interfaces.splitlines()]