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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def dev_version():
 """ Returns a hexdigest of all the python files in the module. """


  md5_hash = hashlib.md5()
  py_files = sorted(list_files(suffix=".py"))
  if not py_files:
    return ''
  for filename in py_files:
    with open(filename, 'rb') as fobj:
      content = fobj.read()
    md5_hash.update(content)
  return md5_hash.hexdigest()