code: def _open_manager_command(self):
      full_name = os.path.join(command_path, manager_commands_file_name)
  
      if self.in_file is not None and self.in_file.closed:
          self.in_file = None
  
      if self.in_file is None and os.path.exists(full_name):
          self.in_file = open(full_name, "rb")
          self.in_file.seek(self.in_offset)
  
file_path: nni/nni/tools/trial_tool/file_channel.py
imports: import os
  from .base_channel import BaseChannel
label_desc: Use image node_id 5 for calling the FileChannel obj's underlying member method code with example usage: obj._open_manager_command() without return types