'Construct and store a PipelineEngine from loader.
If get_loader is None, constructs an ExplodingPipelineEngine'

def init_engine(self, get_loader):

    if (get_loader is not None):
        self.engine = SimplePipelineEngine(get_loader, self.trading_calendar.all_sessions, self.asset_finder)
    else:
        self.engine = ExplodingPipelineEngine()
