Return the list of subdomain operations accepted within a given txid.
        Return {'status': True, 'subdomain_ops': [{...}]} on success
        Return {'error': ...} on error

def rpc_get_subdomain_ops_at_txid(self, txid, **con_info):
        """
        Return the list of subdomain operations accepted within a given txid.
        Return {'status': True, 'subdomain_ops': [{...}]} on success
        Return {'error': ...} on error
        """
        if not check_string(txid, min_length=64, max_length=64, pattern='^[0-9a-fA-F]{64}$'):
            return {'error': 'Not a valid txid', 'http_status': 400}
       
        subdomain_ops = get_subdomain_ops_at_txid(txid)
        return self.success_response( {'subdomain_ops': subdomain_ops} )