code: def check_file_exists(self, remote_cmd=""):
          
          if self.direction == "put":
              if not remote_cmd:
                  remote_cmd = "dir {}{}".format(self.file_system, self.dest_file)
              remote_out = self.ssh_ctl_chan.send_command_expect(remote_cmd)
              search_string = r"{}.*Usage for".format(self.dest_file)
              if "No such file or directory" in remote_out:
                  return False
              elif re.search(search_string, remote_out, flags=re.DOTALL):
                  return True
              else:
                  raise ValueError("Unexpected output from check_file_exists")
          elif self.direction == "get":
              return os.path.exists(self.dest_file)
docs: Check if the dest_file already exists on the file system (return boolean).