docs: def iter_acgt_geno(self):
          """Iterates over genotypes (ACGT format).
  
          Returns:
              tuple: The name of the marker as a string, and its genotypes as a
              :py:class:`numpy.ndarray` (ACGT format).
  
          """
          # Need to iterate over itself, and modify the actual genotypes
          for i, (marker, geno) in enumerate(self.iter_geno()):
              yield marker, self._allele_encoding[i][geno]