How to use the jupyterlab.process.Process._procs.remove function in jupyterlab

def terminate(self):
        """Terminate the process and return the exit code.
        """
        proc = self.proc

        # Kill the process.
        if proc.poll() is None:
            os.kill(proc.pid, signal.SIGTERM)

        # Wait for the process to close.
        try:
            proc.wait()
        finally:
            Process._procs.remove(self)

        return proc.returncode

# Kill the process group if we started a new session.
                os.killpg(os.getpgid(proc.pid), signal.SIGTERM)
            else:
                os.kill(proc.pid, signal.SIGTERM)

        # Close stdout.
        try:
            self._stdout.close()
        except Exception as e:
            pass

        # Wait for the process to close.
        try:
            proc.wait()
        finally:
            Process._procs.remove(self)

        return proc.returncode