'Return a single extra spec item.'

@extensions.expected_errors(404)
def show(self, req, flavor_id, id):

    context = req.environ['nova.context']
    context.can((fes_policies.POLICY_ROOT % 'show'))
    flavor = common.get_flavor(context, flavor_id)
    try:
        return {id: flavor.extra_specs[id]}
    except KeyError:
        msg = (_('Flavor    %(flavor_id)s    has    no    extra    specs    with    key    %(key)s.') % dict(flavor_id=flavor_id, key=id))
        raise webob.exc.HTTPNotFound(explanation=msg)
