JSON Decoder issue

[Cronax3]

Hey community,
currently I am programming a programing which is using the python Bittrex-API wrapper.
I ran into a problem which I am not able to resolve at the moment so I am asking for some help.
I am receiving a current market json file and a pretty confusing error. As you can see having a look at
the ouput I first print out the receiving data from the API wrapper but JSON is complaingin as you can see at
the bottom. I dunno how to fix this :(

Sourcecode:

from bittrex import Bittrex
import json

 
my_bittrex = Bittrex(None, None)
buffer = str(my_bittrex.get_ticker("USDT-BTC")).replace("'",'"')
print(buffer)
parsed_json = json.loads(buffer)
print(parsed_json["Last"])

Just in case you are wondering about the replace function: I used it because the API wrapper returns a json string using single quotes and JSON complained about it. It said I have to use double quotes so I replaced them.
Output:

Output:
{"result": {"Last": 4159.99999999, "Ask": 4159.99999999, "Bid": 4133.0}, "success": True, "message": ""}
Traceback (most recent call last):
  File "/home/pi/C9Workspace/Python/bittrex_test.py", line 8, in <module>
    parsed_json = json.loads(buffer)
  File "/usr/lib/python3.5/json/__init__.py", line 319, in loads
    return _default_decoder.decode(s)
  File "/usr/lib/python3.5/json/decoder.py", line 339, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "/usr/lib/python3.5/json/decoder.py", line 357, in raw_decode
    raise JSONDecodeError("Expecting value", s, err.value) from None
json.decoder.JSONDecodeError: Expecting value: line 1 column 85 (char 84)

[nilamo]

buffer = str(my_bittrex.get_ticker("USDT-BTC")).replace("'",'"')
         ^^^

What type is it before you turn it into a string?

[Cronax3]

The Datatype is 'dict'.
Ok as I realize now I don't need to tread it as a json. Its not meant to be json at all and thats why the decoder is complaining. I misunderstood the api documentation. I completely messed this point up. Didn't even realize its a dict. My problem is solved now. Thanks for the hint!