docs: def check_file_exists(self, remote_cmd="dir home"):
          """Check if the dest_file already exists on the file system (return boolean)."""
          if self.direction == "put":
              remote_out = self.ssh_ctl_chan.send_command_expect(remote_cmd)
              search_string = r"Directory contents .*{}".format(self.dest_file)
              return bool(re.search(search_string, remote_out, flags=re.DOTALL))
          elif self.direction == "get":
              return os.path.exists(self.dest_file)