Resolves error: datetime.datetime(...) is not JSON serializable

examples/google_spreadsheet.py

@@ -115,7 +115,7 @@ def login_open_sheet(oauth_key_file, spreadsheet):
 
     # Append the data in the spreadsheet, including a timestamp
     try:
-        worksheet.append_row((datetime.datetime.now(), temp, humidity))
+        worksheet.append_row((datetime.datetime.now().isoformat(), temp, humidity))
     except:
         # Error appending data, most likely because credentials are stale.
         # Null out the worksheet so a login is performed at the top of the loop.