code: def run_sampler(
      backend,
      nwalkers=32,
      ndim=3,
      nsteps=25,
      seed=1234,
      thin=None,
      thin_by=1,
      progress=False,
      store=True,
  ):
      np.random.seed(seed)
      coords = np.random.randn(nwalkers, ndim)
      sampler = EnsembleSampler(
          nwalkers, ndim, normal_log_prob, backend=backend
      )
      sampler.run_mcmc(
          coords,
          nsteps,
          thin=thin,
          thin_by=thin_by,
          progress=progress,
          store=store,
      )
      return sampler
  
imports: import pickle
  from itertools import islice, product
  import numpy
  import pytest
  from emcee import EnsembleSampler, backends, moves, walkers_independent
label_desc: Use image node_id 4 for calling a global function with example usage: run_sampler(backend, nwalkers, ndim, nsteps, seed, thin, thin_by, progress, store) and returns: sampler