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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 min(self):
 """Minimum, ignoring nans."""

        if "min" not in self.attrs.keys():

            def f(dataset, s):
                return np.nanmin(dataset[s])

            self.attrs["min"] = np.nanmin(list(self.chunkwise(f).values()))
        return self.attrs["min"]