'Clear the widget state.'

def clear(self):

    self.data = None
    self._effective_data = None
    self._matrix = None
    self._mask = None
    self._silhouette = None
    self._labels = None
    self.cluster_var_model[:] = []
    self.annotation_var_model[:] = ['None']
    self._clear_scene()
    self.Error.clear()
    self.Warning.clear()
