code: def ref_shape(x, start, end):
      if start is None:
          start = 0
      if end is None:
          end = 100
      return (x.shape[start:end],)
  
imports: import pytest
  import numpy
  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_shape(x, start, end) and returns: x