Writing json to Azure Table Storage throws type error

[hmqgg]

azure-functions-python-samples/eventhub-trigger-table-out-bindings/function/run.py

Line 46 in ce9ef7a

 json.dump(outdoc,f) 

When I use json.dump(somejson, f), it throws
TypeError: a bytes-like object is required, not 'str'.

And if I use json.dumps(somejson, f), it throws
Microsoft.Azure.WebJobs.Host: Object reference not set to an instance of an object.

It should be

with open(os.environ['someTable'], 'w') as f:
    json.dump(somejson, f);

[Yoichi Kawasaki]

@hmqgg thank you for the feedback.
as you suggested, I modified the mode from binary to text in opening output table:
c189c9c

Thanks alot