code: def topKVertices(katz, col, k):
      top = katz.nlargest(n=k, columns=col)
      top = top.sort_values(by=col, ascending=False)
      return top["vertex"]
  
file_path: cugraph/python/cugraph/cugraph/tests/centrality/test_katz_centrality.py
imports: import gc
  import pytest
  import networkx
  import cudf
  import cugraph
  from cugraph.testing import utils, DEFAULT_DATASETS, UNDIRECTED_DATASETS
  from cugraph.datasets import toy_graph_undirected, karate
label_desc: Use image node_id 2 for calling a global function with example usage: topKVertices(katz, col, k) and returns: top