code: def test_edges_named_without_nodes(self):
      import cudf
  
      g = graphistry.edges(edges2_df, "a", "b")
      G = g.to_cugraph()
      g2 = g.from_cugraph(G)
      assert g2._nodes is None
      g2 = g2.materialize_nodes()
      assert len(g2._nodes) == len(nodes2_df)
      assert len(g2._edges) == len(g._edges)
      g2n = g2._nodes.sort_values(by=g2._node).reset_index(drop=True)
      logger.debug("g2n type :: %s", type(g2n))
      assert g2n.equals(
          cudf.DataFrame(
              {
                  g2._node: ["a", "b", "c", "d"],
              }
          )
      )
  
imports: from functools import lru_cache
  import graphistry, logging, os, pandas, pytest
  from graphistry.tests.common import NoAuthTestCase
  from graphistry.constants import SRC, DST, NODE
  from graphistry.plugins.cugraph import SRC_CUGRAPH, DST_CUGRAPH, NODE_CUGRAPH, from_cugraph, to_cugraph, compute_cugraph, layout_cugraph, compute_algs, node_compute_algs_to_attr, layout_algs
label_desc: Use image node_id 6 for calling the Test_from_cugraph obj's underlying member method code with example usage: obj.test_edges_named_without_nodes() without return types