code: def nodes_without_positions():
      nodes_df = pd.DataFrame({"id": np.arange(5)})
      return nodes_df.set_index("id")
  
file_path: datashader/datashader/tests/test_layout.py
imports: from __future__ import annotations
  import pytest
  import numpy
  import pandas
  from datashader.bundling import directly_connect_edges, hammer_bundle
  from datashader.layout import circular_layout, forceatlas2_layout, random_layout
label_desc: Use image node_id 2 for calling a global function with example usage: nodes_without_positions() and returns: nodes_df