code: def test_nested_arrays_stringlength(self, obj):
      length = len(str(obj))
      expected = np.dtype(f"S{length}")
      arr = np.array(obj, dtype="O")
      assert np.array([arr, arr], dtype="S").dtype == expected
  
imports: from itertools import permutations, product
  import pytest
  from pytest import param
  import numpy
  from numpy.core._rational_tests import rational
  from numpy.core._multiarray_umath import _discover_array_parameters
  from numpy.testing import assert_array_equal, assert_warns, IS_PYPY
label_desc: Use image node_id 2 for calling the TestStringDiscovery obj's underlying member method code with example usage: obj.test_nested_arrays_stringlength(obj) without return types