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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 is_missing(self):
 """Find missing genotype calls. Returns ------- out : ndarray, bool, shape (n_variants, n_samples) Array where elements are True if the genotype call matches the condition. Examples -------- array([[False, False], [False, False], [False, True]]) <GenotypeVector shape=(3, 2) dtype=int64> 0/1 1/1 ./. array([False, False, True]) """


        out = np.any(self.values < 0, axis=-1)

        # handle mask
        if self.mask is not None:
            out |= self.mask

        return out