<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _user_config_file():
 """ Check that the config file is present and readable. If not, copy a template in place. """

    config_file = Constants.USER_CONFIG
    if os.path.exists(config_file) and os.access(config_file, os.R_OK):
        return config_file
    elif os.path.exists(config_file) and not os.access(config_file, os.R_OK):
        raise IOError("Can not read %s" % config_file)
    else:
        shutil.copy(Constants.EXAMPLE_USER_CONFIG, config_file)

        raise JuicerConfigError("Default config file created.\nCheck man 5 juicer.conf.")