code: def a_test_bbvi_mini_batch():
      model = pf.EGARCHMReg(formula="JPM~Rf", data=data, p=1, q=1)
      x = model.fit(
          "BBVI", iterations=100, map_start=False, mini_batch=32
      )
      assert len(model.latent_variables.z_list) == 8
      lvs = np.array([i.value for i in model.latent_variables.z_list])
      assert len(lvs[np.isnan(lvs)]) == 0
  
imports: import numpy
  import pyflux
  import pandas
  from pandas.io.data import DataReader
  from datetime import datetime
label_desc: Use image node_id 4 for calling a global function with example usage: a_test_bbvi_mini_batch() without return types