<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def do_signal(self, signame: str) -> None: """Send a Unix signal"""

        if hasattr(signal, signame):
            os.kill(os.getpid(), getattr(signal, signame))
        else:
            self._sout.write('Unknown signal %s\n' % signame)