Language: Python
Label: vulnerable
CWE: NVD-CWE-noinfo \u2014 

Code:
    def select(self, query: ast.Select) -> pd.DataFrame:

        conditions = extract_comparison_conditions(query.where)
        urls = []
        for op, arg1, arg2 in conditions:

            if op == 'or':
                raise NotImplementedError(f'OR is not supported')

            if arg1 == 'url':
                url = arg2

                if op == '=':
                    urls = [str(url)]
                elif op == 'in':
                    if type(url) == str:
                        urls = [str(url)]
                    else:
                        urls = url
                else:
                    raise NotImplementedError(
                        f'url can be url = "someurl", you can also crawl multiple sites, as follows: url IN ("url1", "url2", ..)')

            else:
                pass

        if len(urls) == 0:
            raise NotImplementedError(
                f'You must specify what url you want to crawl, for example: SELECT * FROM crawl WHERE url IN ("someurl", ..)')

        if query.limit is None:
            raise NotImplementedError(f'You must specify a LIMIT which defines the number of pages to crawl')
        limit = query.limit.value

        if limit < 0:
            limit = 0
            
        result = get_all_websites(urls, limit, html=False)
        if len(result) > limit:
            result = result[:limit]
        # filter targets
        result = project_dataframe(result, query.targets, self.get_columns())
        return result