Store feedback. Keep specified feedback as previous output

		:param feedback: data to store
		:param cr: whether to write carriage return to the end or not
		:return: None

def write_feedback(self, feedback, cr=True):
		""" Store feedback. Keep specified feedback as previous output

		:param feedback: data to store
		:param cr: whether to write carriage return to the end or not
		:return: None
		"""
		self.__previous_data += feedback
		if cr is True:
			self.__previous_data += '\n'