def is_session_storage_enabled(self, subject=None):
if subject.get_session(False):<EOL><INDENT>return True<EOL><DEDENT>if not self.session_storage_enabled:<EOL><INDENT>return False<EOL><DEDENT>if (not hasattr(subject, '<STR_LIT>') and self.session_manager and<EOL>not isinstance(self.session_manager, session_abcs.NativeSessionManager)):<EOL><INDENT>return False<EOL><DEDENT>return subject.web_registry.session_creation_enabled<EOL>
Returns ``True`` if session storage is generally available (as determined
by the super class's global configuration property is_session_storage_enabled
and no request-specific override has turned off session storage, False
otherwise.

This means session storage is disabled if the is_session_storage_enabled
property is False or if a request attribute is discovered that turns off
session storage for the current request.

:param subject: the ``Subject`` for which session state persistence may
                be enabled

:returns: ``True`` if session storage is generally available (as
          determined by the super class's global configuration property
          is_session_storage_enabled and no request-specific override has
          turned off session storage, False otherwise.