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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_user_details(self, response):
 """ Complete with additional information from session, as available. """

        result = {
            'id': response['id'],
            'username': response.get('username', None),
            'email': response.get('email', None),
            'first_name': response.get('first_name', None),
            'last_name': response.get('last_name', None)
        }
        if result['first_name'] and result['last_name']:
            result['fullname'] = result['first_name'] + \
                ' ' + result['last_name']
        return result