def _load(self, time_series):
if not time_series:<EOL><INDENT>return None<EOL><DEDENT>if isinstance(time_series, TimeSeries):<EOL><INDENT>return time_series<EOL><DEDENT>if isinstance(time_series, dict):<EOL><INDENT>return TimeSeries(time_series)<EOL><DEDENT>return TimeSeries(utils.read_csv(time_series))<EOL>
Load time series.
:param time_series: a TimeSeries, a dictionary or a path to a csv file(str).
:return TimeSeries: a TimeSeries object.