def alert_severity_to_dbot_score(severity_str):
    """Converts an severity string to DBot score representation
        alert severity. Can be one of:
        Low    ->  1
        Medium ->  2
        High   ->  3

    Args:
        severity_str: String representation of severity.

    Returns:
        Dbot representation of severity
    """
    severity_str = severity_str.lower()
    if severity_str == 'low':
        return 1
    if severity_str == 'medium':
        return 2
    elif severity_str == 'high':
        return 3
    return 0