code: def sha256(filepath, blocksize=65536):
      
      hasher = hashlib.sha256()
      fo = open(filepath, 'rb')
      buf = fo.read(blocksize)
      while len(buf) > 0:
          hasher.update(buf)
          buf = fo.read(blocksize)
      return hasher.hexdigest()
docs: Generate SHA 256 hash for file at `filepath`