class_docstr: An object that represents an individual's call at a genomic locus.
  
  Parameters
  ----------
  alleles : :obj:`list` of :obj:`int`
      List of alleles that compose the call.
  phased : :obj:`bool`
      If ``True``, the alleles are phased and the order is specified by
      `alleles`.
  
  Note
  ----
  This object refers to the Python value returned by taking or collecting
  Hail expressions, e.g. ``mt.GT.take(5`)``. This is rare; it is much
  more common to manipulate the :class:`.CallExpression` object, which is
  constructed using the following functions:
  
   - :func:`.call`
   - :func:`.unphased_diploid_gt_index_call`
   - :func:`.parse_call`
docstr: Return the genotype index for unphased, diploid calls.
  
  Returns
  -------
  :obj:`int`
docstr_tok: ["Return","the","genotype","index","for","unphased",",","diploid","calls",".","Returns","--","--","--","-",":","obj",":","`","int","`"]
code: def unphased_diploid_gt_index(self):
      """Return the genotype index for unphased, diploid calls.
  
      Returns
      -------
      :obj:`int`
      """
  
      if self.ploidy != 2 or self.phased:
          raise FatalError(
              "'unphased_diploid_gt_index' is only valid for unphased, diploid calls. Found {}.".format(
                  repr(self)
              )
          )
      a0 = self._alleles[0]
      a1 = self._alleles[1]
      assert a0 <= a1
      return a1 * (a1 + 1) / 2 + a0
  
imports: from collections.abc import Sequence
  from hail.typecheck import typecheck_method
  from hail.utils import FatalError
label_desc: Use image node_id 20 for calling the Call obj's underlying member method code with example usage: obj.unphased_diploid_gt_index() and returns: unknown