docs: def get_tag_context(name, state):
      """
      Given a tag name, return its associated value as defined in the current
      context stack.
      """
      new_contexts = 0
      ctm = None
      while True:
          try:
              ctx_key, name = name.split('.', 1)
              ctm = state.context.get(ctx_key)
          except ValueError:
              break
          if not ctm:
              break
          else:
              state.context.push(ctm)
              new_contexts += 1
  
      ctm = state.context.get(name)
  
      return new_contexts, ctm