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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_conf(fn=None):
 """Update global config from YAML file If fn is None, looks in global config directory, which is either defined by the INTAKE_CONF_DIR env-var or is ~/.intake/ . """

    if fn is None:
        fn = cfile()
    if os.path.isfile(fn):
        with open(fn) as f:
            try:
                conf.update(yaml_load(f))
            except Exception as e:
                logger.warning('Failure to load config file "{fn}": {e}'
                               ''.format(fn=fn, e=e))