<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def end_address(self):
 """Get basic block end address. """

        if self._instrs is []:
            return None

        return self._instrs[-1].address + self._instrs[-1].size - 1