json.decoder.JSONDecodeError: Expecting ':' delimiter

import json

json_str = '{"id":235, "brand": "Nike", "qty:84, "status":{"isForSale":true}}'

sneakers = json.loads(json_str)

print (type(sneakers))

print(sneakers['brand'])
print(sneakers['qty'])

Такую ошибку выдаёт

Traceback (most recent call last):
  File "/Users/ols/Desktop/ unitet1/main.py", line 507, in <module>
    sneakers = json.loads(json_str)
  File "/Users/ols/micromamba/lib/python3.9/json/__init__.py", line 346, in loads
    return _default_decoder.decode(s)
  File "/Users/ols/micromamba/lib/python3.9/json/decoder.py", line 337, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "/Users/ols/micromamba/lib/python3.9/json/decoder.py", line 353, in raw_decode
    obj, end = self.scan_once(s, idx)
json.decoder.JSONDecodeError: Expecting ':' delimiter: line 1 column 39 (char 38)