code: def cast_to(x, dtype):
      return x.astype(dtype)
  
imports: import functools
  import numpy
  import nvidia.dali.fn
  import nvidia.dali.ops
  from nvidia.dali import Pipeline
  from nose_utils import assert_raises
  from test_utils import check_output
label_desc: Use image node_id 2 for calling a global function with example usage: cast_to(x, dtype) and returns: x