Firebase initialize

hi i am trying to initialize Firebase for android application of Open Edx, I did change the config.yaml as instructed in the read me but still i am unable to initialize it. It gives the error as follows.
java.lang.IllegalStateException: Default FirebaseApp is not initialized in this process org.edx.mobile. Make sure to call FirebaseApp.initializeApp(Context) first.
at com.google.firebase.FirebaseApp.getInstance(FirebaseApp.java:179)