private boolean shouldAdd(PsiMethod psiMethod) {
    MethodSignature signature = psiMethod.getSignature(PsiSubstitutor.EMPTY);
    PsiMethod previousMethod = myMethodsBySignature.get(signature);
    if (previousMethod == null) return true;
    if (isInheritor(psiMethod, previousMethod)) {
      myAllMembers.remove(previousMethod);
      return true;
    }
    return false;
  }
private boolean shouldAdd(PsiMethod psiMethod)