def parquet(self, path):
        """Loads a Parquet file stream, returning the result as a :class:`DataFrame`.

        You can set the following Parquet-specific option(s) for reading Parquet files:
            * ``mergeSchema``: sets whether we should merge schemas collected from all \
                Parquet part-files. This will override ``spark.sql.parquet.mergeSchema``. \
                The default value is specified in ``spark.sql.parquet.mergeSchema``.

        .. note:: Evolving.

        >>> parquet_sdf = spark.readStream.schema(sdf_schema).parquet(tempfile.mkdtemp())
        >>> parquet_sdf.isStreaming
        True
        >>> parquet_sdf.schema == sdf_schema
        True
        """
        if isinstance(path, basestring):
            return self._df(self._jreader.parquet(path))
        else:
            raise TypeError("path can be only a single string")