code: def test_isscalar():
      assert isscalar("?int32")
      assert isscalar("float32")
      assert isscalar(int32)
      assert isscalar(Categorical(["a", "b", "c"]))
      assert not isscalar("{a: int32, b: float64}")
  
imports: from datashader.datashape.predicates import isfixed, _dimensions, isnumeric, isscalar
  from datashader.datashape.coretypes import TypeVar, int32, Categorical
label_desc: Use image node_id 2 for calling a global function with example usage: test_isscalar() without return types