updating doc string

Author: jsstylos

watson_developer_cloud/visual_recognition_v3.py

@@ -30,7 +30,7 @@ def __init__(self, version, url=default_url, use_vcap_services=True, api_key=Non
         """
         Construct an instance. Fetches service parameters from VCAP_SERVICES
         runtime variable for Bluemix, or it defaults to local URLs.
-        :param version: specifies the specific version-date of the service to use
+        :param version: specifies the specific version-date of the service to use, for example '2016-05-20'
         """
 
         WatsonDeveloperCloudService.__init__(