def get_active_channels_by_year_quarter(<EOL>self, channel_type, year, quarter, expires=None):
if expires is None:<EOL><INDENT>expires = datetime.combine(datetime.utcnow().date(), time.min)<EOL><DEDENT>return self.search_channels(<EOL>type=channel_type, tag_year=year, tag_quarter=quarter,<EOL>expires_after=expires.isoformat())<EOL>
Search for all active channels by year and quarter