docs: def collapse(self, remove=False):
          """
          Move all ``sequence_ids`` in the subtree below this node to this node.
  
          If ``remove`` is True, nodes below this one are deleted from the
          taxonomy.
          """
          descendants = iter(self)
          # Skip this node
          assert next(descendants) is self
          for descendant in descendants:
              self.sequence_ids.update(descendant.sequence_ids)
              descendant.sequence_ids.clear()
  
          if remove:
              for node in self.children:
                  self.remove_child(node)