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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 daily_freezethaw_cycles(tasmax, tasmin, freq='YS'):
 r"""Number of days with a diurnal freeze-thaw cycle The number of days where Tmax > 0℃ and Tmin < 0℃. Parameters tasmax : xarray.DataArray Maximum daily temperature [℃] or [K] tasmin : xarray.DataArray Minimum daily temperature values [℃] or [K] freq : str Resampling frequency Returns ------- xarray.DataArray Number of days with a diurnal freeze-thaw cycle Notes ----- Let :math:`TX_{i}` be the maximum temperature at day :math:`i` and :math:`TN_{i}` be the daily minimum temperature at day :math:`i`. Then the number of freeze thaw cycles during period :math:`\phi` is given by : .. math:: \sum_{i \in \phi} [ TX_{i} > 0℃ ] [ TN_{i} < 0℃ ] where :math:`[P]` is 1 if :math:`P` is true, and 0 if false. """

    frz = utils.convert_units_to('0 degC', tasmax)
    ft = (tasmin < frz) * (tasmax > frz) * 1
    out = ft.resample(time=freq).sum(dim='time')
    return out