docs: def _clear_process(self):
          """
          Close stdin/stdout of subprocess.
  
          It is required because of ResourceWarning in Python 3.
          """
          if self.process:
              if self.process.stdin:
                  self.process.stdin.close()
              if self.process.stdout:
                  self.process.stdout.close()
  
              self.process = None
  
          self._endtime = None