code: def run(self, nodes):
      return [[node, node] for node in nodes]
  
file_path: stellargraph/tests/data/test_unsupervised_sampler.py
imports: import pytest
  import numpy
  from collections import defaultdict
  from stellargraph.data.unsupervised_sampler import UnsupervisedSampler
  from stellargraph.data.explorer import UniformRandomWalk
  from ..test_utils.graphs import line_graph
label_desc: Use image node_id 1 for calling the CustomWalker obj's underlying member method code with example usage: obj.run(nodes) and returns: unknown