'Creates or opens a new session.  Default implementation stores all
session data in a signed cookie.  This requires that the
:attr:`secret_key` is set.  Instead of overriding this method
we recommend replacing the :class:`session_interface`.
.. deprecated: 1.0
Will be removed in 1.1. Use ``session_interface.open_session``
instead.
:param request: an instance of :attr:`request_class`.'

def open_session(self, request):

    warnings.warn(DeprecationWarning('"open_session"    is    deprecated    and    will    be    removed    in    1.1.    Use    "session_interface.open_session"    instead.'))
    return self.session_interface.open_session(self, request)
