parameters: (self, device_serial, default_timeout=_DEFAULT_TIMEOUT,
                 default_retries=_DEFAULT_RETRIES)
docstring: Initializes the FastbootWrapper.
  
      Args:
        device_serial: The device serial number as a string.
docstring_summary: Initializes the FastbootWrapper.
docstring_tokens: Initializes the FastbootWrapper .
function: def __init__(self, device_serial, default_timeout=_DEFAULT_TIMEOUT,
                 default_retries=_DEFAULT_RETRIES):
      """Initializes the FastbootWrapper.
  
      Args:
        device_serial: The device serial number as a string.
      """
      if not device_serial:
        raise ValueError('A device serial must be specified')
      self._device_serial = str(device_serial)
      self._default_timeout = default_timeout
      self._default_retries = default_retries
function_tokens: def __init__ ( self , device_serial , default_timeout = _DEFAULT_TIMEOUT , default_retries = _DEFAULT_RETRIES ) : if not device_serial : raise ValueError ( 'A device serial must be specified' ) self . _device_serial = str ( device_serial ) self . _default_timeout = default_timeout self . _default_retries = default_retries