text: from . import *
  from udsoncan.Response import Response
  from udsoncan.exceptions import *
  
  class TesterPresent(BaseService):
  	_sid = 0x3E
  
  	supported_negative_response = [	Response.Code.SubFunctionNotSupported, 
  							Response.Code.IncorrectMessageLegthOrInvalidFormat
  							]	
  
  	@classmethod
  	def make_request(cls):
  		"""
  		Generates a request for TesterPresent
  		"""		
  		from udsoncan import Request
  		return Request(service=cls, subfunction=0)
  
  	@classmethod
  	def interpret_response(cls, response):
  		"""
  		Populates the response ``service_data`` property with an instance of :class:`TesterPresent.ResponseData<udsoncan.services.TesterPresent.ResponseData>`
  
  		:param response: The received response to interpret
  		:type response: :ref:`Response<Response>`
  
  		:raises InvalidResponseException: If length of ``response.data`` is too short
  		"""		
  		if  len(response.data) < 1:
  			raise InvalidResponseException(response, "Response data must be at least 1 bytes")
  
  		response.service_data = cls.ResponseData()
  		response.service_data.subfunction_echo = response.data[0]
  
  	class ResponseData(BaseResponseData):
  		"""
  		.. data:: subfunction_echo
  
  			Requests subfunction echoed back by the server. This value should always be 0
  		"""		
  		def __init__(self):
  			super().__init__(TesterPresent)
  			self.subfunction_echo = None
  