Fix for #214 JSON parse failure on 204 No Content response (#216)

* Update rest_session.py

Add Python version check. 3.7 minimum required.

* Fix for #214 JSON parse failure on 204 No Content response

Fixes #214
There are very few GETs in Meraki dashboard API that produce 204 No Content, for which the Python equivalent is None, but for those that do, this change bypasses the attempt to JSON parse if the content is None, which produced an error.

meraki/rest_session.py

@@ -389,7 +389,12 @@ def _get_pages_legacy(self, metadata, url, params=None, total_pages=-1, directio
         metadata['page'] = 1
 
         response = self.request(metadata, 'GET', url, params=params)
-        results = response.json()
+
+        # Handle GETs that produce 204 No Content responses, e.g. getOrganizationClientSearch
+        if response.status_code == 204:
+            results = None
+        else:
+            results = response.json()
 
         # For event log endpoint when using 'next' direction, so results/events are sorted chronologically
         if type(results) == dict and metadata['operation'] == 'getNetworkEvents' and direction == 'next':