/**
Default constructor.
- @beginWxPythonOnly
- The following methods are added in wxPython for accessing the object:
- - GetData(): Returns a reference to the Python Object.
- - SetData(obj): Associates a new Python Object with the wxTreeItemData.
- @endWxPythonOnly
-
@beginWxPerlOnly
In wxPerl the constructor accepts a scalar as an optional parameter
and stores it as client data; use