code: AppAuth getAppAuthorizationByAppId(String appId) {
  		String where = Contract.COLUMN_APP_IDENTIFIER + " = ?";
  		String args[] = { appId };
  		Cursor c = mRegistryTable.getReadableDatabase().query(Contract.TABLE_NAME, null, where, args, null, null, null);
  		AppAuth auth = null;
  		if (c.moveToFirst()) {
  			auth = appAuthFromCursor(c);
  		}
  		c.close();
  		return auth;
  	}
docs: Retrieves an appauth given the identifier of an application
  
  @param appId
  - the Id of the application
  @return the appAuth of the application, or null if the app is not
  installed