code: def _get_node(self, loc_descriptor, create_non_existing_nodes=False):
          
          node = self._root_node
  
          for location in loc_descriptor.generate_all_sub_locations():
              child = node.get_child_node_or_default(location, None)
              if child is None:
                  if not create_non_existing_nodes:
                      raise RuntimeError("Node at location '%s' in '%s' does not exist!" % (location, loc_descriptor.to_string()))
                  else:
                      # create empty node
                      child = TreeMapNode(None)
                      node.set_child_node(location, child)
                      self._nbr_of_nodes += 1
              node = child
  
          return node
docs: Get node corresponding to last location in a :class:`LocationDescriptor` object.
          
          Args:
              loc_descriptor: A  :class:`LocationDescriptor` object
              create_non_existing_nodes (bool): Do we create non existing nodes along the way (including last node)?
          
          Raises:
              RuntimeError if a node along the path given in by the :class:`LocationDescriptor` object does not exist
              **if** ``create_non_existing_nodes`` is set to ``False``.