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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 dry_lapse(pressure, temperature, ref_pressure=None):
 r"""Calculate the temperature at a level assuming only dry processes. This function lifts a parcel starting at `temperature`, conserving potential temperature. The starting pressure can be given by `ref_pressure`. Parameters pressure : `pint.Quantity` The atmospheric pressure level(s) of interest temperature : `pint.Quantity` The starting temperature ref_pressure : `pint.Quantity`, optional The reference pressure. If not given, it defaults to the first element of the pressure array. Returns ------- `pint.Quantity` The resulting parcel temperature at levels given by `pressure` See Also -------- moist_lapse : Calculate parcel temperature assuming liquid saturation processes parcel_profile : Calculate complete parcel profile potential_temperature """

    if ref_pressure is None:
        ref_pressure = pressure[0]
    return temperature * (pressure / ref_pressure)**mpconsts.kappa