docs: def view_focused_activity(self) -> str:
          '''View focused activity.'''
          output, _ = self._execute(
              '-s', self.device_sn, 'shell', 'dumpsys', 'activity', 'activities')
          return re.findall(r'mFocusedActivity: .+(com[a-zA-Z0-9\.]+/.[a-zA-Z0-9\.]+)', output)[0]