code: def test_multi_hdf5():
      with backends.TempHDFBackend() as backend1:
          run_sampler(backend1)
  
          backend2 = backends.HDFBackend(
              backend1.filename, name="mcmc2"
          )
          run_sampler(backend2)
          chain2 = backend2.get_chain()
  
          with h5py.File(backend1.filename, "r") as f:
              assert set(f.keys()) == {backend1.name, "mcmc2"}
  
          backend1.reset(10, 2)
          assert np.allclose(backend2.get_chain(), chain2)
          with pytest.raises(AttributeError):
              backend1.get_chain()
  
file_path: emcee/src/emcee/tests/unit/test_backends.py
imports: import os
  from itertools import product
  from os.path import join
  import numpy
  import pytest
  from emcee import EnsembleSampler, State, backends
  from emcee.backends.hdf import does_hdf5_support_longdouble
label_desc: Use image node_id 11 for calling a global function with example usage: test_multi_hdf5() without return types