def METHOD_NAME(self) -> Dict[str, Dict]:
    """
    Return current data schema of connection.
    Returns
    -------
    Dict[str, Dict]
        Data schema of current connection.
    """
    if not self._schema:
        if not self.data_files:
            self.connect()
        # read the first row of each file to get the schema
        iter_data_files = (
            tqdm(self.data_files.items())
            if self._progress
            else self.data_files.items()
        )
        for table, files in iter_data_files:
            if not files:
                continue
            sample_df = pd.read_json(files[0], lines=True, nrows=1)
            self._schema[table] = {
                col: dtype.name for col, dtype in sample_df.dtypes.to_dict().items()
            }
        logger.info("Reading schema for %d tables", len(self.data_files))
    return self._schema