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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_config_file(user, config):
    '''
    Get absolute path to a user's ssh_config.
    '''
    uinfo = __salt__['user.info'](user)
    if not uinfo:
        raise CommandExecutionError('User \'{0}\' does not exist'.format(user))
    home = uinfo['home']
    config = _expand_authorized_keys_path(config, user, home)
    if not os.path.isabs(config):
        config = os.path.join(home, config)
    return config