code: def key_from_password(password):
      
      if isinstance(password, unicode):
          password = password.encode('utf-8')
      if not isinstance(password, bytes):
          raise TypeError("password must be byte string, not %s" % type(password))
      
      sha = SHA256.new()
      sha.update(password)
      return sha.digest()
docs: This method just hashes self.password.