How to check if Android app installed on the phone

I want to check if the Android app is installed on the phone, if not - open the Google Play. I tried this code:

     `AndroidJavaClass up = new AndroidJavaClass ("com.unity3d.player.UnityPlayer");
     AndroidJavaObject ca = up.GetStatic<AndroidJavaObject> ("currentActivity");
     AndroidJavaObject packageManager = ca.Call<AndroidJavaObject> ("getPackageManager");
     Debug.Log (" ********LaunchOtherApp ");
     AndroidJavaObject launchIntent = null;
     //if the app is installed, no errors. Else, doesn't get past next line
     try {
         
         launchIntent = packageManager.Call<AndroidJavaObject> ("getLaunchIntentForPackage", "com.blah.blah");
              
             ca.Call ("startActivity", launchIntent);
                     
         
     } catch (UnityException e) {
         Debug.Log ("exception" + e.Message);
         Application.OpenURL ("market://details?q=pname:com.blah.blah");
     }`    

But it isn't working, because there must be Exception, and not Unity Exception. Can anyone help me?