<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def clear(self):
 """ Clears plot by removing all actors and properties """

        for renderer in self.renderers:
            renderer.RemoveAllViewProps()
        self._scalar_bar_slots = set(range(MAX_N_COLOR_BARS))
        self._scalar_bar_slot_lookup = {}
        self._scalar_bar_ranges = {}
        self._scalar_bar_mappers = {}
        self._scalar_bar_actors = {}
        self._scalar_bar_widgets = {}