code: def start(self):
      super(OptimizerBarFeed, self).start()
  
imports: import abc
  from pyalgotrade import bar
  from pyalgotrade.dataseries import bards
  from pyalgotrade import feed
  from pyalgotrade import dispatchprio
label_desc: Use image node_id 4 for calling the OptimizerBarFeed obj's underlying member method code with example usage: obj.start() without return types