input: 
  def sha256(data):
      """Compute the SHA-256 hash of the given data.
      
      >>> sha256('hello')
      '2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824'
      >>> sha256('world')
      '486ea46224d1bb4fb680f34f7c9ad96a8f24ec88be73ea8e5a6c65260e9cb8a7'
      """
      hash_function = hashlib.sha256()
      hash_function.update(data.encode('utf-8'))
      return hash_function.hexdigest()
  
output:     import hashlib