docs: convert print statement to function (#988)

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Fixes #987 🦕

Author: atenni

docs/start.md

@@ -98,7 +98,7 @@ The response is a Python object built from the JSON response sent by the API ser
 ```python
 import json
 ...
-print json.dumps(response, sort_keys=True, indent=4)
+print(json.dumps(response, sort_keys=True, indent=4))
 ```
 
 For example, if the printed JSON is the following: