code: def sim_timetrace_bg2(emission, max_rate, bg_rate, t_step, rs=None):
      
      if rs is None:
          rs = np.random.RandomState()
      emiss_bin_rate = np.zeros((emission.shape[0] + 1, emission.shape[1]),
                                dtype='float64')
      emiss_bin_rate[:-1] = emission * max_rate * t_step
      if bg_rate is not None:
          emiss_bin_rate[-1] = bg_rate * t_step
          counts = rs.poisson(lam=emiss_bin_rate).astype('uint8')
      else:
          counts = rs.poisson(lam=emiss_bin_rate[:-1]).astype('uint8')
      return counts
docs: Draw random emitted photons from r.v. ~ Poisson(emission_rates).
  
      This is an alternative implementation of :func:`sim_timetrace_bg`.