code: def sha1_of_file(filename):
      h = hashlib.sha1()
      with open(filename, "rb") as f:
          h.update(f.read())
      return h.hexdigest()
  
file_path: pyflux/tools/cythonize.py
imports: from __future__ import division, print_function, absolute_import
  import os
  import re
  import sys
  import hashlib
  import subprocess
label_desc: Use image node_id 4 for calling a global function with example usage: sha1_of_file(filename) and returns: h