Iterates on available markers.

        Returns:
            Genotypes instances.

def iter_genotypes(self):
        """Iterates on available markers.

        Returns:
            Genotypes instances.

        """
        # Parsing each column of the dataframe
        for variant in self.df.columns:
            genotypes = self.df.loc[:, variant].values
            info = self.map_info.loc[variant, :]

            yield Genotypes(
                Variant(info.name, info.chrom, info.pos, [info.a1, info.a2]),
                genotypes,
                reference=info.a2,
                coded=info.a1,
                multiallelic=False,
            )