code: def block_test_sfn(data, msk, myrad, bcast_var, extra_params):
      outmat = data[0][:, :, :, 0]
      outmat[~msk] = None
      if myrad == 0:
          return outmat
      else:
          return outmat[myrad:-myrad, myrad:-myrad, myrad:-myrad]
  
file_path: brainiak/tests/searchlight/test_searchlight.py
imports: from collections import namedtuple
  import numpy
  from mpi4py import MPI
  import conftest
  from brainiak.searchlight.searchlight import Searchlight
  from brainiak.searchlight.searchlight import Diamond, Ball
label_desc: Use image node_id 10 for calling a global function with example usage: block_test_sfn(data, msk, myrad, bcast_var, extra_params) and returns: outmat, outmat