private void ShowHierarchy(XmlSchemaSet schemaSet, TextWriter writer)
{
var schema = schemaSet.Schemas(Constants.InvoiceTargetNamespace).Cast<XmlSchema>().Single();
prefixLookup = schema.Namespaces.ToArray().Where(v => !string.IsNullOrEmpty(v.Name)).ToDictionary(k => k.Namespace, v => v.Name);
PrintSchemaDetail(schema, writer);
var prefixes = schemaSet.GetNamespacePrefixes();
Console.WriteLine();
foreach (var prefix in prefixes)
{
writer.WriteLine($"{prefix.Name,9}: -> \"{prefix.Namespace}\"");
}
}