private static @Nullable PsiParameter getFunctionalParameter(ULambdaExpression function) {
    UCallExpression call = ObjectUtils.tryCast(function.getUastParent(), UCallExpression.class);
    if (call != null) {
      return getParameter(call, function);
    }
    return null;
  }
private static @Nullable PsiParameter getFunctionalParameter(ULambdaExpression function)