code: def test_nested():
      assert_dshape_equal(
          dshape("var * {a: 3 * {b: int32}}"),
          dshape("var * {a: 3 * {b: int32}}"),
      )
  
      with pytest.raises(AssertionError) as e:
          assert_dshape_equal(
              dshape("var * {a: 3 * {b: int32}}"),
              dshape("var * {a: 3 * {b: float32}}"),
          )
      assert "'int32' != 'float32'" in str(e.value)
      assert "_.measure['a'].measure['b'].name" in str(e.value)
  
file_path: datashader/datashader/datashape/util/tests/test_testing.py
imports: import pytest
  from datashader.datashape.coretypes import DateTime, R, String, Time, TimeDelta, Tuple, Option, int32, float32
  from datashader.datashape.util import dshape
  from datashader.datashape.util.testing import assert_dshape_equal
label_desc: Use image node_id 9 for calling a global function with example usage: test_nested() without return types