@property<EOL><INDENT>def start_date(self):<DEDENT>
return self._start_date<EOL>
Gets the start_date of this DateRange.
String in `YYYY-MM-DD` format, e.g. `2017-10-31` per the ISO 8601 extended format for calendar dates. The beginning of a date range (inclusive)

:return: The start_date of this DateRange.
:rtype: str