code: def compute_n_digit_freqs(filename, n):
      """
      Read digits of pi from a file and compute the n digit frequencies.
      """
      d = txt_file_to_digits(filename)
      freqs = n_digit_freqs(d, n)
      return freqs
  
file_path: ipyparallel/docs/source/examples/pi/pidigits.py
imports: import os
  from urllib.request import urlretrieve
  import numpy
  from matplotlib import pyplot
label_desc: Use image node_id 5 for calling a global function with example usage: compute_n_digit_freqs(filename, n) and returns: freqs