Problems finding an attribute attached to a Type

Assembly a = Assembly.LoadFile(file);
foreach (Type t in a.GetTypes())
{
    object[] attr = t.GetCustomAttributes(typeof(SchemeNameAttribute), false);

    foreach (object attribute in attr)
    {
        SchemeNameAttribute schemeName = attribute as SchemeNameAttribute;
        if (schemeName != null && schemeName.Name.ToLower() == brickName.ToLower() )
        {
            return t;
        }
    }
}

object[] attr = t.GetCustomAttributes(false);

SchemeNameAttribute schemeName = attribute as SchemeNameAttribute;