public void onOverriddenMethod(@NotNull PsiMethod baseMethod, @NotNull PsiMethod overridingMethod) {
    PsiClass clazz = baseMethod.getContainingClass();
    if (clazz == null) {
      return;
    }
    List<OverriddenMethodPair> methods = myOverriddenMethods.get(clazz);
    if (methods == null) {
      myOverriddenMethods.put(clazz, methods = new ArrayList<>());
    }
    methods.add(new OverriddenMethodPair(baseMethod, overridingMethod));
  }
public void onOverriddenMethod(@NotNull PsiMethod baseMethod, @NotNull PsiMethod overridingMethod)