code: def keys():
      return numpy.array([4, 2, 6, 1, 8, 7, 9, 3, 30])
  
file_path: thinc/thinc/tests/layers/test_mappers.py
imports: import numpy
  import pytest
  from thinc.layers import premap_ids, remap_ids, remap_ids_v2
label_desc: Use image node_id 1 for calling a global function with example usage: keys() and returns: numpy