           (signature String, Function)
         create        :
           (signature Object, Function)
-        # all           :
-        #   (signature Function)
+        some          : [
+          (signature Object, Function)
+          (signature Object, Object, Function)
+        ]
       instance        :
         delete        :
           (signature Function)

    callback err
    return true

  @create = permit 'create credential',

    success: (client, data, callback)->

              return  if failed err, callback, credential, credData
              callback null, credential


  @one$: permit 'list credentials',

    success: (client, publicKey, callback)->

      options  = { limit : 1 }
      selector = { publicKey }

      {delegate} = client.connection
      delegate.fetchCredentials {},
        targetOptions : {
          selector, options
        }, (err, res = [])->
          callback err, res[0]


  @some$: permit 'list credentials',

    success: (client, selector, options, callback)->

      [options, callback] = [callback, options]  unless callback
      options ?= { limit : 10 }

      {delegate} = client.connection
      delegate.fetchCredentials {},
        targetOptions : {
          selector, options
        }, callback


  delete: permit

    advanced: [
