code: def send_signal(self, signum):
          
          if self._process is None:
              raise RuntimeError('no child process')
          self._process.kill(signum)
docs: Send the signal *signum* to the child.
  
          On Windows, SIGTERM, SIGKILL and SIGINT are emulated using
          TerminateProcess(). This will cause the child to exit unconditionally
          with status 1. No other signals can be sent on Windows.