text: import hashlib
  import argparse
  
  parser = argparse.ArgumentParser()
  parser.add_argument('filename')
  args = parser.parse_args()
  
  filename = args.filename
  BLOCK_SIZE = 1024*1024*16
  
  file_hash = hashlib.sha512()
  with open(filename, 'rb') as f:
      fb = f.read(BLOCK_SIZE)
      while len(fb) > 0:
          file_hash.update(fb)
          fb = f.read(BLOCK_SIZE)
  
  # print('SHA-512 of {}:'.format(filename))
  print (file_hash.hexdigest())
  