code: def test_pagerank_string_vertex_ids(dask_client):
      """
      Ensures string vertex IDs can be used.
  
      Note: the dask_client fixture sets up and tears down a LocalCUDACluster.
      See ../conftest.py
      """
      # Use pandas and to_csv() to create a CSV file that can be read in by both
      # dask_cudf and cudf.
      df = cudf.DataFrame(
          {
              "src": ["a1", "a1", "a2", "a3"],
              "dst": ["a2", "a3", "a4", "a4"],
          }
      )
      # SG
      G = cugraph.Graph(directed=True)
      G.from_cudf_edgelist(df, source="src", destination="dst")
  
      sg_results = cugraph.pagerank(G)
      sg_results = sg_results.sort_values("vertex").reset_index(
          drop=True
      )
  
      # MG
      ddf = dask_cudf.from_cudf(df, npartitions=2)
      G_dask = cugraph.Graph(directed=True)
      G_dask.from_dask_cudf_edgelist(
          ddf, source="src", destination="dst"
      )
  
      mg_results = dcg.pagerank(G_dask)
      # Organize results for easy comparison, this does not change the values. MG
      # Pagerank defaults to float64, so convert to float32 when comparing to SG
      mg_results = (
          mg_results.compute()
          .sort_values("vertex")
          .reset_index(drop=True)
      )
      mg_results["pagerank"] = mg_results["pagerank"].astype("float32")
  
      assert_frame_equal(sg_results, mg_results)
  
imports: import gc
  import pytest
  import pandas
  import numpy
  import dask
  import cudf
  import dask_cudf
  import cugraph.dask
  import cugraph
  from cugraph.testing import utils
  from cugraph.structure.number_map import NumberMap
  from cugraph.dask.common.mg_utils import is_single_gpu
  from cugraph.testing.utils import RAPIDS_DATASET_ROOT_DIR_PATH
  from cudf.testing import assert_frame_equal, assert_series_equal
label_desc: Use image node_id 6 for calling a global function with example usage: test_pagerank_string_vertex_ids(dask_client) without return types