code: def delete_password(self, service, username):
          
          try:
              key_name = self._key_for_service(service)
              hkey = winreg.OpenKey(
                  winreg.HKEY_CURRENT_USER, key_name, 0,
                  winreg.KEY_ALL_ACCESS)
              winreg.DeleteValue(hkey, username)
              winreg.CloseKey(hkey)
          except WindowsError:
              e = sys.exc_info()[1]
              raise PasswordDeleteError(e)
          self._delete_key_if_empty(service)
docs: Delete the password for the username of the service.