return error if get_grid reques is not ok

Author: Kully

plotly/plotly/plotly.py

@@ -1484,6 +1484,15 @@ def get_grid(grid_url, raw=False):
 
     # make request to grab the grid id (fid)
     r_meta = requests.get(meta_get_url, headers=headers)
+
+    # check if request is ok
+    if not r_meta.ok:
+        raise exceptions.PlotlyError(
+            "Whoops, you got a 404 response. Your grid url {} may be "
+            "pointing to a plot rather than a grid. If it is a grid, make "
+            "sure your grid is 'public' and not 'private' or 'secret'."
+        )
+
     json_res_meta = json.loads(r_meta.text)
     retrieved_grid_id = json_res_meta['fid']