Fatal Exception: java.lang.IllegalStateException: activity must not be null

1. 에러 내용: Fatal Exception: java.lang.IllegalStateException: activity must not be null at hbs.com.timetablescreen.Fragment.CheckTimeFragment$onCreateView$1.onEvent(CheckTimeFragment.kt:90) at hbs.com.timetablescreen.Fragment.CheckTimeFragment$onCreateView$1.onEvent(CheckTimeFragment.kt:36) at com.google.firebase.firestore.DocumentReference.lambda$addSnapshotListenerInternal$2(com.google.firebase:..