docs: def md5sum(self):
          """
          Check to see if the file exists on the device
          :return:
          """
          cmd = 'show file {dir}:{bin} md5sum'.format(
              dir=self.DESTDIR, bin=self.image)
  
          run = self.device.api.exec_opcmd
          try:
              got = run(cmd)
              return got.get('file_content_md5sum').strip()
          except:  # NOQA
              return None