old_contents: # -*- coding: utf-8 -*-
  
  from __future__ import division, print_function, absolute_import
  
  import os
  from scipy.signal import firwin, lfilter
  from sprocket.util import HDF5
  
  
  def low_cut_filter(x, fs, cutoff=70):
      """Low cut filter
  
      Parameters
      ---------
      x : array, shape(`samples`)
          Waveform sequence
      fs: array, int
          Sampling frequency
      cutoff : float,
          Cutoff frequency of low cut filter
          Default set to 70 [Hz]
  
      Returns
      ---------
      lcf_x : array, shape(`samples`)
          Low cut filtered waveform sequence
      """
  
      nyquist = fs // 2
      norm_cutoff = cutoff / nyquist
  
      # low cut filter
      fil = firwin(255, norm_cutoff, pass_zero=False)
      lcf_x = lfilter(fil, 1, x)
  
      return lcf_x
  
  
  def read_feats(listf, h5dir, ext='mcep'):
      """HDF5 handler
      Create list consisting of arrays listed in the list
  
      Parameters
      ---------
      listf : str,
          Path of list file
      h5dir : str,
          Path of hdf5 directory
      ext : str,
          `mcep` : mel-cepstrum
          `f0` : F0
  
      Returns
      ---------
      datalist : list of arrays
  
      """
  
      datalist = []
      with open(listf, 'r') as fp:
          for line in fp:
              f = line.rstrip()
              h5f = os.path.join(h5dir, f + '.h5')
              h5 = HDF5(h5f, mode='r')
              datalist.append(h5.read(ext))
              h5.close()
  
      return datalist
  
new_contents: # -*- coding: utf-8 -*-
  
  from __future__ import division, print_function, absolute_import
  
  import os
  from scipy.signal import firwin, lfilter
  from sprocket.util import HDF5
  
  
  def low_cut_filter(x, fs, cutoff=70):
      """Low cut filter
  
      Parameters
      ---------
      x : array, shape(`samples`)
          Waveform sequence
      fs: array, int
          Sampling frequency
      cutoff : float, optional
          Cutoff frequency of low cut filter
          Default set to 70 [Hz]
  
      Returns
      ---------
      lcf_x : array, shape(`samples`)
          Low cut filtered waveform sequence
      """
  
      nyquist = fs // 2
      norm_cutoff = cutoff / nyquist
  
      # low cut filter
      fil = firwin(255, norm_cutoff, pass_zero=False)
      lcf_x = lfilter(fil, 1, x)
  
      return lcf_x
  
  
  def read_feats(listf, h5dir, ext='mcep'):
      """HDF5 handler
      Create list consisting of arrays listed in the list
  
      Parameters
      ---------
      listf : str,
          Path of list file
      h5dir : str,
          Path of hdf5 directory
      ext : str,
          `mcep` : mel-cepstrum
          `f0` : F0
  
      Returns
      ---------
      datalist : list of arrays
  
      """
  
      datalist = []
      with open(listf, 'r') as fp:
          for line in fp:
              f = line.rstrip()
              h5f = os.path.join(h5dir, f + '.h5')
              h5 = HDF5(h5f, mode='r')
              datalist.append(h5.read(ext))
              h5.close()
  
      return datalist
  
subject: add optional to cutoff