docs: def path(self, tax_ids):
          """Get the node at the end of the path described by tax_ids."""
          assert tax_ids[0] == self.tax_id
          if len(tax_ids) == 1:
              return self
  
          n = tax_ids[1]
          try:
              child = next(i for i in self.children if i.tax_id == n)
          except StopIteration:
              raise ValueError(n)
  
          return child.path(tax_ids[1:])