Update client.py (#81)

Added 'next_url' parameter to tickers v3 to support pagination

Author: jcho-polygon

polygon/rest/client.py

@@ -38,8 +38,8 @@ def reference_tickers(self, **query_params) -> models.ReferenceTickersApiRespons
         endpoint = f"{self.url}/v2/reference/tickers"
         return self._handle_response("ReferenceTickersApiResponse", endpoint, query_params)
 
-    def reference_tickers_v3(self, **query_params) -> models.ReferenceTickersV3ApiResponse:
-        endpoint = f"{self.url}/v3/reference/tickers"
+   def reference_tickers_v3(self, next_url=None, **query_params) -> models.ReferenceTickersV3ApiResponse:
+        endpoint = f"{self.url}/v3/reference/tickers" if not next_url else next_url
         return self._handle_response("ReferenceTickersV3ApiResponse", endpoint, query_params)
 
     def reference_ticker_types(self, **query_params) -> models.ReferenceTickerTypesApiResponse: