@Nullable
    private static Integer extractEmptyLengthCheck(@NotNull PsiExpression expression, PsiVariable targetBuilder) {
      PsiMethodCallExpression maybeEmptyCall = tryCast(BoolUtils.getNegated(expression), PsiMethodCallExpression.class);
      if (!EMPTY_LENGTH.test(maybeEmptyCall)) return null; // extract call matcher
      if (!ExpressionUtils.isReferenceTo(maybeEmptyCall.getMethodExpression().getQualifierExpression(), targetBuilder)) return null;
      return 0;
    }
@Nullable
    private static Integer extractEmptyLengthCheck(@NotNull PsiExpression expression, PsiVariable targetBuilder)