code: def main_activity(self):
          
          x = set()
          y = set()
          for item in self._dom.getElementsByTagName("activity"):
              for sitem in item.getElementsByTagName("action"):
                  val = sitem.getAttribute("android:name")
                  if val == "android.intent.action.MAIN":
                      x.add(item.getAttribute("android:name"))
              for sitem in item.getElementsByTagName("category"):
                  val = sitem.getAttribute("android:name")
                  if val == "android.intent.category.LAUNCHER":
                      y.add(item.getAttribute("android:name"))
          z = x.intersection(y)
          if len(z) > 0:
              return z.pop()
          return None
docs: Returns:
              the name of the main activity