Convert a pandas.DataFrame to list of records that can be used to make a DataFrame
         :return list of records

def _convert_from_pandas(self, pdf, schema, timezone):
        """
         Convert a pandas.DataFrame to list of records that can be used to make a DataFrame
         :return list of records
        """
        if timezone is not None:
            from pyspark.sql.types import _check_series_convert_timestamps_tz_local
            copied = False
            if isinstance(schema, StructType):
                for field in schema:
                    # TODO: handle nested timestamps, such as ArrayType(TimestampType())?
                    if isinstance(field.dataType, TimestampType):
                        s = _check_series_convert_timestamps_tz_local(pdf[field.name], timezone)
                        if s is not pdf[field.name]:
                            if not copied:
                                # Copy once if the series is modified to prevent the original
                                # Pandas DataFrame from being updated
                                pdf = pdf.copy()
                                copied = True
                            pdf[field.name] = s
            else:
                for column, series in pdf.iteritems():
                    s = _check_series_convert_timestamps_tz_local(series, timezone)
                    if s is not series:
                        if not copied:
                            # Copy once if the series is modified to prevent the original
                            # Pandas DataFrame from being updated
                            pdf = pdf.copy()
                            copied = True
                        pdf[column] = s

        # Convert pandas.DataFrame to list of numpy records
        np_records = pdf.to_records(index=False)

        # Check if any columns need to be fixed for Spark to infer properly
        if len(np_records) > 0:
            record_dtype = self._get_numpy_record_dtype(np_records[0])
            if record_dtype is not None:
                return [r.astype(record_dtype).tolist() for r in np_records]

        # Convert list of numpy records to python lists
        return [r.tolist() for r in np_records]