# File lib/fog/rackspace/compute.rb, line 220
         def authenticate(options={})
            super({
             :rackspace_api_key  => @rackspace_api_key,
             :rackspace_username => @rackspace_username,
             :rackspace_auth_url => @rackspace_auth_url,
             :connection_options => @connection_options
           })
         end