Troubelshooting raise TypeError("quote_from_bytes() expected bytes")

I have an error raised by the following piece of code

    def __to_canonical_querystring_post(self, params):    canonical_querystring = ""    # parameters have to be sorted alphabetically for the signing part    for param_key, param_value in sorted(params.items()):        if canonical_querystring != "":            canonical_querystring += "&"        canonical_querystring += param_key +"="+ urllib.parse.quote(param_value)    return canonical_querystring

The params are Make_Payment_params = {"debitAccountNumber": 12003189487,"creditAccountNumber": 12065812627,"amount": 100,"requestedExecutionDate": "2019-03-09"}

and the error is raise TypeError("quote_from_bytes() expected bytes")TypeError: quote_from_bytes() expected bytes

Help is much appreciated