def __init__(self, title, normalized_progress, subtitle=None, subevent=None):
self._title = title<EOL>self._subtitle = subtitle<EOL>self._subevent = subevent<EOL>self._normalized_progress = normalized_progress<EOL>
Constructor.

:param title: The title of the event
:type title: str
:param subtitle: More detail about the event
:type subtitle: str
:param subevent: An event object describing the current state of the service's
    progress toward readiness
:type subevent: Event
:param normalized_progress: The fractional representation of the status of the event
:type normalized_progress: float