Helper-functions to ensure string starts/ends with a specific string

StringEnsureStartsEndsWithExtensions.cs

public static class StringExtensions
{
    public static string EnsureEndsWith(
        this string value,
        string endValue,
        StringComparison comparisonType = StringComparison.CurrentCulture)
    {
        return (value == null || value.EndsWith(endValue, comparisonType)) ? value : (value + endValue);
    }

    public static string EnsureStartsWith(
        this string value,
        string startValue,
        StringComparison comparisonType = StringComparison.CurrentCulture)
    {
        return (value == null || value.StartsWith(startValue, comparisonType)) ? value : (startValue + value);
    }
}