def get_additional_occurrences(self, start, end):
        """
        Return persisted occurrences which are now in the period
        """
        return [occ for key, occ in self.lookup.items() if (
            (end and occ.start < end) and
            occ.end >= start and not occ.cancelled)]
def get_additional_occurrences ( self , start , end ) : return [ occ for key , occ in self . lookup . items ( ) if ( ( end and occ . start < end ) and occ . end >= start and not occ . cancelled ) ]
Return persisted occurrences which are now in the period