code: def login(self, username: str='anonymous', password: str='-wpull-lib@'):
          '''Log in.
  
          Coroutine.
          '''
          yield from self._control_stream.write_command(Command('USER', username))
  
          reply = yield from self._control_stream.read_reply()
  
          if reply.code == ReplyCodes.user_logged_in_proceed:
              return
  
          self.raise_if_not_match(
              'Login username', ReplyCodes.user_name_okay_need_password, reply)
  
          yield from self._control_stream.write_command(Command('PASS', password))
  
          reply = yield from self._control_stream.read_reply()
  
          self.raise_if_not_match(
              'Login password', ReplyCodes.user_logged_in_proceed, replyf login(self, username: str='anonymous', password: str='-wpull-lib@'):
          '''Log in.
  
          Coroutine.
          '''
          yield from self._control_stream.write_command(Command('USER', username))
  
          reply = yield from self._control_stream.read_reply()
  
          if reply.code == ReplyCodes.user_logged_in_proceed:
              return
  
          self.raise_if_not_match(
              'Login username', ReplyCodes.user_name_okay_need_password, reply)
  
          yield from self._control_stream.write_command(Command('PASS', password))
  
          reply = yield from self._control_stream.read_reply()
  
          self.raise_if_not_match(
              'Login password', ReplyCodes.user_logged_in_proceed, reply)
docs: Log in.
  
          Coroutine.