'Parse the JSON response body.
If the access token request is valid and authorized, the
authorization server issues an access token as described in
`Section 5.1`_.  A refresh token SHOULD NOT be included.  If the request
failed client authentication or is invalid, the authorization server
returns an error response as described in `Section 5.2`_.
:param body: The response body from the token request.
:param scope: Scopes originally requested.
:return: Dictionary of token parameters.
:raises: Warning if scope has changed. OAuth2Error if response is invalid.
These response are json encoded and could easily be parsed without
the assistance of OAuthLib. However, there are a few subtle issues
to be aware of regarding the response which are helpfully addressed
through the raising of various errors.
A successful response should always contain
**access_token**
The access token issued by the authorization server. Often
a random string.
**token_type**
The type of the token issued as described in `Section 7.1`_.
Commonly ``Bearer``.
While it is not mandated it is recommended that the provider include
**expires_in**
The lifetime in seconds of the access token.  For
example, the value "3600" denotes that the access token will
expire in one hour from the time the response was generated.
If omitted, the authorization server SHOULD provide the
expiration time via other means or document the default value.
**scope**
Providers may supply this in all responses but are required to only
if it has changed since the authorization request.
.. _`Section 5.1`: http://tools.ietf.org/html/rfc6749#section-5.1
.. _`Section 5.2`: http://tools.ietf.org/html/rfc6749#section-5.2
.. _`Section 7.1`: http://tools.ietf.org/html/rfc6749#section-7.1'

def parse_request_body_response(self, body, scope=None, **kwargs):

    self.token = parse_token_response(body, scope=scope)
    self._populate_attributes(self.token)
    return self.token
