code: def create_stellargraph():
      nodes = pd.DataFrame(
          [[1, 1], [1, 0], [0, 1], [0.5, 1]], index=["a", "b", "c", "d"]
      )
      edges = pd.DataFrame(
          [
              ("a", "b", 1.0),
              ("b", "c", 0.4),
              ("a", "c", 2.0),
              ("b", "d", 10.0),
          ],
          columns=["source", "target", "weight"],
      )
      return StellarGraph(nodes, edges)
  
file_path: stellargraph/tests/mapper/test_cluster_gcn_node_mapper.py
imports: from stellargraph.mapper import ClusterNodeGenerator, ClusterNodeSequence
  from stellargraph.core.graph import StellarGraph
  import pandas
  import numpy
  import pytest
  from ..test_utils.graphs import example_graph_random
label_desc: Use image node_id 1 for calling a global function with example usage: create_stellargraph() and returns: StellarGraph