Clean azure blob storage container name

AzureStorageStorageHelper.cs

public static bool IsValidContainer(string containerName)
{
    // Container names must be valid DNS names, and must conform to these rules:
    // * Container names must start with a letter or number, and can contain only letters, numbers, and the dash (-) character.
    // * Every dash (-) character must be immediately preceded and followed by a letter or number; consecutive dashes are not permitted in container names.
    // * All letters in a container name must be lowercase.
    // * Container names must be from 3 through 63 characters long.

    // $root is a special container that can exist at the root level and is always valid.
    if (containerName.Equals("$root"))
        return false;

    //if (!Regex.IsMatch(containerName, @"^[a-z0-9](([a-z0-9\-[^\-])){1,61}[a-z0-9]$"))
    if (!Regex.IsMatch(containerName, @"^(([a-z\d]((-(?=[a-z\d]))|([a-z\d])){2,62})|(\$root))$")) return false;

    return true;
}