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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 new_reservoir(reservoir_type='uniform', *reservoir_args, **reservoir_kwargs):
 """ Build a new reservoir """


    try:
        reservoir_cls = RESERVOIR_TYPES[reservoir_type]
    except KeyError:
        raise InvalidMetricError("Unknown reservoir type: {}".format(reservoir_type))

    return reservoir_cls(*reservoir_args, **reservoir_kwargs)