code: def test_isfixed():
      assert not isfixed(TypeVar("M") * int32)
  
imports: from datashader.datashape.predicates import isfixed, _dimensions, isnumeric, isscalar
  from datashader.datashape.coretypes import TypeVar, int32, Categorical
label_desc: Use image node_id 1 for calling a global function with example usage: test_isfixed() without return types