def calculate_cost_timeseries(consumption_timeseries,
rate=CUBIC_METER_FLAT_RATE):
timestep_kwargs = dict([
(attr, getattr(consumption_timeseries.time_step, attr))
for attr in ('length_minutes', 'length_months',
'interval_type', 'nominal_offset', 'actual_offset')])
time_step = TimeStep(**timestep_kwargs)
result = Timeseries(time_step = time_step)
for timestamp in consumption_timeseries:
result[timestamp] = monthly_cost_from_consumption(
consumption_timeseries[timestamp], rate=rate)
return result
