void (@NotNull PyCallExpression node) { if (parameterWasReassigned.get()) return; Optional .ofNullable(node.getCallee()) .filter(callee -> "len".equals(callee.getName()) && isReferenceToParameter(node.getArgument(0, PyReferenceExpression.class))) .map(PyExpression::getReference) .map(PsiReference::resolve) .filter(element -> PyBuiltinCache.getInstance(element).isBuiltin(element)) .ifPresent(callable -> usedAttributes.add(PyNames.LEN)); super.visitPyCallExpression(node); }