code: def test_array(self, ls, global_dtype_str, expected_dtype):
      gs.set_default_dtype(global_dtype_str)
  
      out = gs.array(ls)
      self.assertDtype(out.dtype, expected_dtype)
  
imports: import random
  import numpy
  import pytest
  import scipy
  import geomstats.backend
  from geomstats.test.test_case import TestCase
  from geomstats.test.vectorization import generate_vectorization_data
label_desc: Use image node_id 3 for calling the DtypeTestCase obj's underlying member method code with example usage: obj.test_array(ls, global_dtype_str, expected_dtype) without return types