PyBuiltinCache (@Nullable PsiElement reference) { if (reference != null) { try { Sdk sdk = findSdkForFile(reference.getContainingFile()); if (sdk != null) { return PythonSdkPathCache.getInstance(reference.getProject(), sdk).getBuiltins(); } } catch (PsiInvalidElementAccessException ignored) { } } return DUD_INSTANCE; // a non-functional fail-fast instance, for a case when skeletons are not available }