Unescape json string

To decode API response string to JSON, json.decode() works fine. This will parse a JSON string similar to
{ “Response” : {“Responsecode” : “1” , “Response” : “Success”}}

But the response comes in the deserialized form like :
“{\”Response\” : {\”Responsecode\” : \”0\” , \”Response\” : \”Success\”}}”
json.decode() won’t work. I searched but couldn’t find how to unescape characters in a string