code: def ref_bit_shift(x, shift, direction):
      if direction == "LEFT":
          return x << shift
      elif direction == "RIGHT":
          return x >> shift
      else:
          raise ValueError("Invalid direction: {}".format(direction))
  
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_bit_shift(x, shift, direction) and returns: unknown, unknown