'Terminate (and then kill) the process launched to process the file.
:param sigkill: whether to issue a SIGKILL if SIGTERM doesn\'t work.
:type sigkill: bool'

def terminate(self, sigkill=False):

    if (self._process is None):
        raise AirflowException(u'Tried    to    call    stop    before    starting!')
    self._result_queue = None
    self._process.terminate()
    self._process.join(5)
    if (sigkill and self._process.is_alive()):
        logging.warning(u'Killing    PID    %s', self._process.pid)
        os.kill(self._process.pid, signal.SIGKILL)
