message: Plug PackageName parameter in Python
diff: @@ -171,7 +171,7 @@ namespace AutoRest.Python.Model
  public virtual bool HasAnyModel => ModelTemplateModels.Any();
  - public string PackageName => Name.ToPythonCase().Replace("_", "");
  + public string PackageName => Settings.Instance.PackageName.Else(Name.ToPythonCase().Replace("_", ""));
  //TODO: Proper namespace validation and formatting
  public string modelNamespace => Namespace.Else(Name.ToPythonCase()).ToLower();
  