Get the genotype of a marker using it's name.

        Args:
            name (str): The name of the marker.
            variant_info (pandas.Series): The marker information (e.g. seek).

        Returns:
            list: A list of Genotypes (only one for PyPlink, see note below).

        Note
        ====
            From PyPlink version 1.3.2 and onwards, each name is unique in the
            dataset. Hence, we can use the 'get_geno_marker' function and be
            sure only one variant is returned.

def get_variant_by_name(self, name, variant_info=None):
        """Get the genotype of a marker using it's name.

        Args:
            name (str): The name of the marker.
            variant_info (pandas.Series): The marker information (e.g. seek).

        Returns:
            list: A list of Genotypes (only one for PyPlink, see note below).

        Note
        ====
            From PyPlink version 1.3.2 and onwards, each name is unique in the
            dataset. Hence, we can use the 'get_geno_marker' function and be
            sure only one variant is returned.

        """
        # From 1.3.2 onwards, PyPlink sets unique names.
        if not self.has_index:
            raise NotImplementedError("Not implemented when IMPUTE2 file is "
                                      "not indexed (see genipe)")

        # Getting the seek position
        if variant_info is None:
            try:
                variant_info = self._impute2_index.loc[name, :]

            except KeyError:
                if name in self.get_duplicated_markers():
                    # The variant is a duplicated one, so we go through all the
                    # variants with the same name and the :dupx suffix
                    return [
                        self.get_variant_by_name(dup_name).pop()
                        for dup_name in self.get_duplicated_markers()[name]
                    ]

                else:
                    # The variant is not in the index
                    logging.variant_name_not_found(name)
                    return []

        # Seeking to the right place in the file
        self._impute2_file.seek(variant_info.seek)

        # Parsing the file
        genotypes = self._parse_impute2_line(self._impute2_file.readline())

        # Fixing the object
        self._fix_genotypes_object(genotypes, variant_info)

        return [genotypes]