code: def _autodetect_fs(self, cmd="dir", pattern=r"Directory of (.*)/"):
          
          if not self.check_enable_mode():
              raise ValueError("Must be in enable mode to auto-detect the file-system.")
          output = self.send_command_expect(cmd)
          match = re.search(pattern, output)
          if match:
              file_system = match.group(1)
              # Test file_system
              cmd = "dir {}".format(file_system)
              output = self.send_command_expect(cmd)
              if "% Invalid" in output or "%Error:" in output:
                  raise ValueError(
                      "An error occurred in dynamically determining remote file "
                      "system: {} {}".format(cmd, output)
                  )
              else:
                  return file_system
  
          raise ValueError(
              "An error occurred in dynamically determining remote file "
              "system: {} {}".format(cmd, output)
          )
docs: Autodetect the file system on the remote device. Used by SCP operations.