class_docstr: Class containing information about nuclear family relatedness and sex.
  
  :param str s: Sample ID of proband.
  
  :param fam_id: Family ID.
  :type fam_id: str or None
  
  :param pat_id: Sample ID of father.
  :type pat_id: str or None
  
  :param mat_id: Sample ID of mother.
  :type mat_id: str or None
  
  :param is_female: Sex of proband.
  :type is_female: bool or None
code: def _to_fam_file_line(self):
      def sample_id_or_else_zero(sample_id):
          if sample_id is None:
              return "0"
          return sample_id
  
      line_list = [
          sample_id_or_else_zero(self._fam_id),
          self._s,
          sample_id_or_else_zero(self._pat_id),
          sample_id_or_else_zero(self._mat_id),
          self._sex_as_numeric_string(),
          "0",
      ]
      return "\t".join(line_list)
  
imports: import re
  from collections import Counter
  from hail.typecheck import typecheck_method, nullable, sequenceof
  from hail.utils.java import Env, FatalError, warning
label_desc: Use image node_id 15 for calling the Trio obj's underlying member method code with example usage: obj._to_fam_file_line() and returns: str, sample_id, str