docs: def update_firmware(filename,
                      host=None,
                      admin_username=None,
                      admin_password=None):
      '''
      Updates firmware using local firmware file
  
      .. code-block:: bash
  
           salt dell dracr.update_firmware firmware.exe
  
      This executes the following command on your FX2
      (using username and password stored in the pillar data)
  
      .. code-block:: bash
  
           racadm update –f firmware.exe -u user –p pass
  
      '''
      if os.path.exists(filename):
          return _update_firmware('update -f {0}'.format(filename),
                                  host=None,
                                  admin_username=None,
                                  admin_password=None)
      else:
          raise CommandExecutionError('Unable to find firmware file {0}'
                                      .format(filename))