def METHOD_NAME(self, type):
    """Create a serializer with the specified type and hourly time step.
    If the serializer had the same time step as the one used in
    _create_timeseries(), then the serializer would be invalid because of violation
    of the unique key (timeseries_group, type, time_step). We choose a different
    time step so that it won't be invalid for this reason. We want to check whether
    it's invalid because of attempting to create two initial (or two checked, or two
    regularized) time series for the same time series group.
    """
    return TimeseriesSerializer(
        data={
            "type": type,
            "timeseries_group": self.timeseries_group.id,
            "time_step": "H",
        }
    )