'Exchange third party credentials for an edx access token, and return a
serialized access token response.'

def exchange_access_token(self, request, user, scope, client):

    if constants.SINGLE_ACCESS_TOKEN:
        edx_access_token = self.get_access_token(request, user, scope, client)
    else:
        edx_access_token = self.create_access_token(request, user, scope, client)
    return self.access_token_response(edx_access_token)
