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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_het(self, allele=None):
 """Find genotype calls that are heterozygous. Returns ------- out : ndarray, bool, shape (n_variants, n_samples) Array where elements are True if the genotype call matches the condition. allele : int, optional Heterozygous allele. Examples -------- array([[False, True], [ True, False], [ True, False]]) array([[False, False], [False, False], [ True, False]]) <GenotypeVector shape=(3, 2) dtype=int64> 0/0 0/1 0/2 array([False, True, True]) """


        allele1 = self.values[..., 0, np.newaxis]  # type: np.ndarray
        other_alleles = self.values[..., 1:]  # type: np.ndarray
        out = np.all(self.values >= 0, axis=-1) & np.any(allele1 != other_alleles, axis=-1)
        if allele is not None:
            out &= np.any(self.values == allele, axis=-1)

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

        return out