private void registerAnnotationByNullAssignmentStatus(PsiVariable variable) {
    if (variableNeverAssignedNull(variable)) {
      registerNotNullAnnotation(variable);
    }
    else if (variableSometimesAssignedNull(variable)) {
      registerNullableAnnotation(variable);
    }
  }
private void registerAnnotationByNullAssignmentStatus(PsiVariable variable)