Add example for bluemix cos api keys

Author: bassel-zeidan

python/README.md

@@ -32,7 +32,7 @@ within a DSX Jupyter notebook, you can obtain your account credentials in the fo
 If your Object Storage was created with a Softlayer account, each part of the credentials will
 be found as text that you can copy and paste into the example code below.
 
-### CloudObjectStorage / Data Science Experience
+### Softlayer CloudObjectStorage / Data Science Experience
 ```python
 import ibmos2spark
 
@@ -50,6 +50,29 @@ object_name = 'file1'
 data = sc.textFile(cos.url(object_name, bucket_name))
 ```
 
+### Bluemix CloudObjectStorage / Data Science Experience
+The class CloudObjectStorage allows you to connect to bluemix cos. You can connect to bluemix using api keys
+as follows:
+
+```pythonw
+import ibmos2spark
+
+# @hidden_cell
+credentials = {
+    'endpoint': 'XXX',
+    'api_key': 'XXX',
+    'service_id': 'XXX'
+}
+
+configuration_name = 'os_bluemix_cos_config'
+cos = ibmos2spark.CloudObjectStorage(sc, credentials, configuration_name, 'bluemix_cos')
+
+bucket_name = 'bucket_name'
+object_name = 'file_name'
+data = sc.textFile(cos.url(object_name, bucket_name))
+```
+
+
 ### Bluemix / Data Science Experience
 
 ```python

python/ibmos2spark/osconfig.py

@@ -188,7 +188,7 @@ def __init__(self, sparkcontext, credentials, configuration_name='', cos_type='s
               * endpoint [required]
               * service_id [required]
               * api_key OR iam_token depends on the selected authorization method (auth_method) [required]
-              * iam_service_endpoint [optional]
+              * iam_service_endpoint [optional] (default: https://iam.ng.bluemix.net/oidc/token)
               * v2_signer_type [optional]
 
         configuration_name [optional]: string that identifies this configuration. You can