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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(self, user_name=None):
 """ Retrieve information about the specified user. If the user_name is not specified, the user_name is determined implicitly based on the AWS Access Key ID used to sign the request. :type user_name: string :param user_name: The name of the user to delete. If not specified, defaults to user making request. """

        params = {}
        if user_name:
            params['UserName'] = user_name
        return self.get_response('GetUser', params)