code: def ref_bool_gather(gdata, mask):
      mask_bool = mask.astype(bool)
      return gdata[mask_bool]
  
file_path: nnabla/python/test/function/test_bool_gather.py
imports: import pytest
  import numpy
  import nnabla
  import nnabla.functions
  from nbla_test_utils import list_context
label_desc: Use image node_id 1 for calling a global function with example usage: ref_bool_gather(gdata, mask) and returns: gdata