parse API JSON response

When I want to generate a new token to give to teslafi, I have to enter a number of fields that come from the tesla API response to the oauth/token request. It would save a lot of time if I could just cut and paste the JSON response from tesla that looks like this:

{
    "access_token": "xxx",
    "token_type": "bearer",
    "expires_in": 3888000,
    "refresh_token": "xxx",
    "created_at": 1535465729
}

and teslafi could just pull out the fields it needs.