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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def group(self, coords):
 """return CoordGroups that can be used to send to queues Each CoordGroup represents a message that can be sent to a particular queue, stamped with the queue_id. The list of coords, which can be 1, is what should get used for the payload for each queue message. """


        groups = []
        for i in range(len(self.zoom_range_items)):
            groups.append([])

        # first group the coordinates based on their queue
        for coord in coords:
            for i, zri in enumerate(self.zoom_range_items):
                toi_match = zri.in_toi is None or \
                            (coord in self.toi_set) == zri.in_toi
                if zri.start <= coord.zoom < zri.end and toi_match:
                    groups[i].append(coord)
                    break

        # now, we need to just verify that for each particular group,
        # should they be further grouped, eg by a particular zoom 10
        # tile
        for i, zri in enumerate(self.zoom_range_items):
            group = groups[i]
            if not group:
                continue
            if zri.group_by_zoom is None:
                for coord in group:
                    yield CoordGroup([coord], zri.queue_id)
            else:
                by_parent_coords = defaultdict(list)
                for coord in group:
                    if coord.zoom >= zri.group_by_zoom:
                        group_coord = coord.zoomTo(zri.group_by_zoom)
                        group_key = coord_marshall_int(group_coord)
                        by_parent_coords[group_key].append(coord)
                    else:
                        # this means that a coordinate belonged to a
                        # particular queue but the zoom was lower than
                        # the group by zoom
                        # this probably shouldn't happen
                        # should it be an assert instead?
                        yield CoordGroup([coord], zri.queue_id)

                for group_key, coords in by_parent_coords.iteritems():
                    yield CoordGroup(coords, zri.queue_id)