code: def test_get_fs_by_requester_pays_config(cls):
      config_1 = "foo"
      config_2 = ("foo", ["bar", "baz", "bat"])
      kwargs_1 = {"gcs_requester_pays_configuration": config_1}
      kwargs_2 = {"gcs_requester_pays_configuration": config_2}
      fses = GCSRequesterPaysFSCache(cls)
      assert fses[None]._gcs_kwargs == {}
      assert fses[config_1]._gcs_kwargs == kwargs_1
      set_kwargs = fses[config_2]._gcs_kwargs
      assert (
          set_kwargs["gcs_requester_pays_configuration"][0]
          == config_2[0]
      )
      assert len(
          set_kwargs["gcs_requester_pays_configuration"][1]
      ) == len(config_2[1])
      assert set(
          set_kwargs["gcs_requester_pays_configuration"][1]
      ) == set(config_2[1])
      default_kwargs_fses = GCSRequesterPaysFSCache(
          cls, {"gcs_kwargs": kwargs_1}
      )
      assert default_kwargs_fses[None]._gcs_kwargs == kwargs_1
  
imports: import pytest
  from hailtop.aiotools.router_fs import RouterAsyncFS
  from hailtop.fs.router_fs import RouterFS
  from hailtop.utils import async_to_blocking
  from hailtop.utils.gcs_requester_pays import GCSRequesterPaysFSCache
label_desc: Use image node_id 1 for calling a global function with example usage: test_get_fs_by_requester_pays_config(cls) without return types