'Creates a new theme.
It is an error if themename already exists. If parent is
specified, the new theme will inherit styles, elements and
layouts from the specified parent theme. If settings are present,
they are expected to have the same syntax used for theme_settings.'

def theme_create(self, themename, parent=None, settings=None):

    script = (_script_from_settings(settings) if settings else '')
    if parent:
        self.tk.call(self._name, 'theme', 'create', themename, '-parent', parent, '-settings', script)
    else:
        self.tk.call(self._name, 'theme', 'create', themename, '-settings', script)
