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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_display_name(self, userid):
        '''Given a Slack userid, grabs user display_name from api.

        Args:
            userid (string): the user id of the user being queried
        Returns:
            dict: a dictionary of the api response
        '''

        user_info = self.slack_client.api_call('users.info', user=userid)
        if user_info.get('ok'):
            user = user_info.get('user')
            if user.get('profile'):
                return user.get('profile').get('display_name')
            else:
                return user.get('name')
        else:
            return userid