code: def _inner_receive(self):
      messages = []
  
      if self.in_file is None:
          self._open_manager_command()
      if self.in_file is not None:
          self.in_file.seek(0, os.SEEK_END)
          new_offset = self.in_file.tell()
          self.in_file.seek(self.in_offset, os.SEEK_SET)
          count = new_offset - self.in_offset
          if count > 0:
              self.in_cache += self.in_file.read(count)
              self.in_offset = new_offset
              messages, self.in_cache = self._fetch_message(
                  self.in_cache, True
              )
      return messages
  
file_path: nni/nni/tools/trial_tool/file_channel.py
imports: import os
  from .base_channel import BaseChannel
label_desc: Use image node_id 6 for calling the FileChannel obj's underlying member method code with example usage: obj._inner_receive() and returns: messages