code: def reload(self):
          
          # Get reload mode
          reload_mode = self._reload_mode
  
          # If reload mode is `exec`
          if self._reload_mode == self.RELOAD_MODE_V_EXEC:
              # Call `reload_using_exec`
              self.reload_using_exec()
  
          # If reload mode is `spawn_exit`
          elif self._reload_mode == self.RELOAD_MODE_V_SPAWN_EXIT:
              # Call `reload_using_spawn_exit`
              self.reload_using_spawn_exit()
  
          # If reload mode is `spawn_wait`
          elif self._reload_mode == self.RELOAD_MODE_V_SPAWN_WAIT:
              # Call `reload_using_spawn_wait`
              self.reload_using_spawn_wait()
  
          # If reload mode is none of above
          else:
              # Get error message
              error_msg = 'Invalid reload mode: {}.'.format(repr(reload_mode))
  
              # Raise error
              raise ValueError(error_msg)
docs: Reload the program.
  
          :return:
              None.