code: def get_level(self, level, relations=None, **args):
          
          g = self.get_filtered_graph(relations)
          nodes = self.get_roots(relations=relations, **args)
          for i in range(level):
              logger.info(" ITERATING TO LEVEL: {} NODES: {}".format(i, nodes))
              nodes = [c for n in nodes
                       for c in g.successors(n)]
          logger.info(" FINAL: {}".format(nodes))
          return nodes
docs: Get all nodes at a particular level
  
          Arguments
          ---------
          relations : list[str]
              list of relations used to filter