code: def bin_spikes(spike_times, binsz):
      
      bins = np.empty((len(spike_times),), dtype=int)
      for i, stime in enumerate(spike_times):
          # around to fix rounding errors
          bins[i] = np.floor(np.around(stime/binsz, 5))
      return bins
docs: Sort spike times into bins
  
      :param spike_times: times of spike instances
      :type spike_times: list
      :param binsz: length of time bin to use
      :type binsz: float
      :returns: list of bin indicies, one for each element in spike_times