code: def iter_by_parent_childs(self, featuretype="gene", level=None,
                                order_by=None, reverse=False,
                                completely_within=False):
          
          # Get all the parent records of the requested feature type
          parent_recs = self.all_features(featuretype=featuretype)
          # Return a generator of these parent records and their
          # children
          for parent_rec in parent_recs:
              unit_records = \
                  [parent_rec] + list(self.children(parent_rec.id))
              yield unit_records
docs: For each parent of type `featuretype`, yield a list L of that parent
          and all of its children (`[parent] + list(children)`). The parent will
          always be L[0].
  
          This is useful for "sanitizing" a GFF file for downstream tools.
  
          Additional kwargs are passed to :meth:`FeatureDB.children`, and will
          therefore only affect items L[1:] in each yielded list.