code: def test_broadcast_with_scalar_kwargs(self) -> None:
      stackers = ["a", "b", "c", "d"]
      kws = bps.double_stack(
          stackers, "start", "end", foo=10, bar="baz"
      )
      assert len(kws) == len(stackers)
      for i, kw in enumerate(kws):
          assert {"start", "end", "foo", "bar", "name"} == set(
              kw.keys()
          )
          assert list(kw["start"]["expr"].fields) == stackers[:i]
          assert list(kw["end"]["expr"].fields) == stackers[: (i + 1)]
          assert kw["foo"] == 10
          assert kw["bar"] == "baz"
          assert kw["name"] == stackers[i]
  
imports: from __future__ import annotations
  import pytest
  import bokeh.plotting._stack
label_desc: Use image node_id 5 for calling the Test_double_stack obj's underlying member method code with example usage: obj.test_broadcast_with_scalar_kwargs() without return types