C# console helper (colors and bold)

ConsoleEx.cs

using System;

sealed class ConsoleEx
{
    public void Write(ConsoleColor color, string format, params object[] arg)
    {
        var current = Console.ForegroundColor;
        Console.ForegroundColor = color;
        Console.Write(format, arg);
        Console.ForegroundColor = current;
    }

    public void WriteLine(ConsoleColor color, string format, params object[] arg) =>
        Write(color, $"{format}\n", arg);

    public void WriteBold(string format, params object[] arg) =>
        Console.Write($"\x1b[1m{format}\x1b[0m", arg);

    public void WriteBoldLine(string format, params object[] arg) =>
       WriteBold($"{format}\n", arg);
}