'Return the named subwidget (which must have been created by
the sub-class).'

def subwidget(self, name):

    n = self._subwidget_name(name)
    if (not n):
        raise TclError, ((('Subwidget    ' + name) + '    not    child    of    ') + self._name)
    n = n[(len(self._w) + 1):]
    return self._nametowidget(n)
