code: def make_step(cls):
      args = {}
      if hasattr(cls, "step_args"):
          args.update(cls.step_args)
      return pm.Metropolis(**args)
  
imports: import arviz
  import numpy
  import numpy.testing
  import pytensor.tensor
  from scipy import stats
  import pymc
  from pymc.backends.arviz import to_inference_data
  from pymc.util import get_var_name
label_desc: Use image node_id 1 for calling the MetropolisFixture obj's underlying member method code with example usage: obj.make_step(cls) and returns: pm