I am getting the TypeError: 'int' object is not subscriptable on the line `sig_data = sig_data[0:file_length_num]` in the following code -

```
def create_slice_from_wav(file_path, file_len, slice_len, step_size):
  #read in wav file
  samp_freq, sig_data = sf.read(file_path)

  #convert file_length from min to sample numbers
  file_length_num = 5*samp_freq*60

  #convert slice_len from ms to sample numbers
  slice_sample_num = slice_len*samp_freq/1000

  #use only slices within file_length
  sig_data = sig_data[0:file_length_num]

  #determine number of samples and length
  n_samples = sig_data.shape[0]
  sig_len = n_samples/samp_freq
  print('Length: ' + str(sig_len) + ' sec')

```