code: def test_sign(xp, device, input, dtypes):
      (in_dtype,), out_dtype = dtypes
      a = xp.array(input.astype(in_dtype))
      return xp.sign(a)
  
imports: import chainer
  import numpy
  import pytest
  import chainerx
  import chainerx.testing
  from chainerx_tests import array_utils
  from chainerx_tests import dtype_utils
  from chainerx_tests import math_utils
  from chainerx_tests import op_utils
label_desc: Use image node_id 2 for calling a global function with example usage: test_sign(xp, device, input, dtypes) and returns: xp