Return True if the tcpdump command can be started

def _check_tcpdump():
    """
    Return True if the tcpdump command can be started
    """
    with open(os.devnull, 'wb') as devnull:
        try:
            proc = subprocess.Popen([conf.prog.tcpdump, "--version"],
                                    stdout=devnull, stderr=subprocess.STDOUT)
        except OSError:
            return False

    if OPENBSD:
        # 'tcpdump --version' returns 1 on OpenBSD 6.4
        return proc.wait() == 1
    else:
        return proc.wait() == 0