code: def create_test_weighted_graph(is_multigraph=False):
      """
      Creates a simple graph for testing the weighted biased random walk class. The node ids are string or integers.
  
      :return: .
      """
      nodes = pd.DataFrame(
          index=[
              "0",
              1,
              2,
              3,
              4,
              5,
              6,
              7,
              8,
              9,
              10,
              "self loner",
              "loner",
          ]
      )
      edges = pd.DataFrame(
          [
              ("0", 1, 3),
              ("0", 2, 4),
              (1, 3, 1),
              (1, 4, 7),
              (3, 6, 9),
              (4, 7, 2),
              (4, 8, 5),
              (2, 5, 7),
              (5, 9, 5),
              (5, 10, 6),
              ("0", "0", 7),
              (1, 1, 8),
              (3, 3, 8),
              (6, 6, 9),
              (4, 4, 1),
              (7, 7, 2),
              (8, 8, 3),
              (2, 2, 4),
              (5, 5, 5),
              (9, 9, 6),
              (
                  "self loner",
                  "self loner",
                  0,
              ),  # an isolated node with a self link
          ],
          columns=["source", "target", "weight"],
      )
  
      return StellarGraph(nodes, edges)
  
imports: import numpy
  import pandas
  import pytest
  import networkx
  from stellargraph.data.explorer import BiasedRandomWalk
  from stellargraph.core.graph import StellarGraph
  from ..test_utils.graphs import create_test_graph, example_graph_random
label_desc: Use image node_id 1 for calling a global function with example usage: create_test_weighted_graph(is_multigraph) and returns: StellarGraph