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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 load_clients_file(filename, configuration_class=ClientConfiguration):
 """ Loads client configurations from a YAML file. :param filename: YAML file name. :type filename: unicode | str :param configuration_class: Class of the configuration object to create. :type configuration_class: class :return: A dictionary of client configuration objects. :rtype: dict[unicode | str, dockermap.map.config.client.ClientConfiguration] """

    with open(filename, 'r') as f:
        return load_clients(f, configuration_class=configuration_class)