code: def load_family_details(self, pheno_covar):
          
          file = open(self.fam_details)
          header = file.readline()
          format = file.readline()
          self.file_index = 0
  
          mask_components = []        # 1s indicate an individual is to be masked out
          for line in file:
              words = line.strip().split()
              indid = ":".join(words[0:2])
              if DataParser.valid_indid(indid):
                  mask_components.append(0)
                  sex = int(words[5])
                  pheno = float(words[6])
                  pheno_covar.add_subject(indid, sex, pheno)
              else:
                  mask_components.append(1)
          mask_components = numpy.array(mask_components)
          self.ind_mask = numpy.zeros(len(mask_components) * 2, dtype=numpy.int8).reshape(-1, 2)
          self.ind_mask[0:, 0] = mask_components
          self.ind_mask[0:, 1] = mask_components
          self.ind_count = self.ind_mask.shape[0]
          pheno_covar.freeze_subjects()
docs: Load family data updating the pheno_covar with  family ids found.
  
          :param pheno_covar: Phenotype/covariate object
          :return: None