code: def batch_cholesky(x, upper):
      L = np.linalg.cholesky(x)
      return np.transpose(L, axes=(0, 2, 1)) if upper else L
  
imports: import pytest
  import numpy
  import nnabla.functions
  from nbla_test_utils import list_context, function_tester
label_desc: Use image node_id 1 for calling a global function with example usage: batch_cholesky(x, upper) and returns: unknown