code: def highlight_nodes(graph: BELGraph, nodes: Optional[Iterable[BaseEntity]] = None, color: Optional[str]=None):
      
      color = color or NODE_HIGHLIGHT_DEFAULT_COLOR
      for node in nodes if nodes is not None else graph:
          graph.node[node][NODE_HIGHLIGHT] = color
docs: Adds a highlight tag to the given nodes.
  
      :param graph: A BEL graph
      :param nodes: The nodes to add a highlight tag on
      :param color: The color to highlight (use something that works with CSS)