docs: def get_plan(self, nodes=None):
          """
          Retrieve a plan, e.g. a list of fixtures to be loaded sorted on
          dependency.
  
          :param list nodes: list of nodes to be loaded.
          :return:
          """
          if nodes:
              plan = self.graph.resolve_nodes(nodes)
          else:
              plan = self.graph.resolve_node()
  
          return plan