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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 prep_system(run_info_yaml, bcbio_system=None):
 """Prepare system configuration information from an input configuration file. This does the work of parsing the system input file and setting up directories for use in 'organize'. """

    work_dir = os.getcwd()
    config, config_file = config_utils.load_system_config(bcbio_system, work_dir)
    dirs = setup_directories(work_dir, os.path.normpath(os.path.dirname(os.path.dirname(run_info_yaml))),
                             config, config_file)
    return [dirs, config, run_info_yaml]