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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 read_config(conf_dir=DEFAULT_CONFIG_DIR):
    "Find and read config file for a directory, return None if not found."

    conf_path = os.path.expanduser(conf_dir)
    if not os.path.exists(conf_path):
        # only throw if not default
        if conf_dir != DEFAULT_CONFIG_DIR:
            raise IOError("Config directory not found at %s" % (conf_path, ))

    return munge.load_datafile('config', conf_path, default=None)