def check_cutoff_value(criterion, cutoff_value):
    """Validate single cutoff value from config file."""
    if criterion == 'lognorm':
        if cutoff_value > 0 and cutoff_value < 1:
            pass
        else:
            exit(
                'Invalid lognorm quantile cutoff value "{}". The cutoffs must be numbers greater than 0 and less than 1.'
                .format(cutoff_value))
    elif criterion == 'mean':
        if cutoff_value > 1:
            pass
        elif cutoff_value > 0 and cutoff_value < 1:
            print(
                'WARNING: cutoff value "{}" is less than 1 mean. Did you intend to specify "lognorm" as criterion?'
                .format(cutoff_value))
        elif cutoff_value < 0:
            exit(
                'Invalid mean cutoff value "{}". Cutoffs must be greater than 0.'
                )
