text: import abc
  
  class entryalgo_abc(metaclass=abc.ABCMeta):
  	@abc.abstractmethod
  	def __init__(self):
  		pass
  
  	@abc.abstractmethod
  	def postprocessor(self):
  		pass
  
  	# -- return None if okay to exec open
  	# -- otherwise, return reason message
  	@abc.abstractmethod
  	def exec_open_final_check(self,symbol,bar):
  		pass
  
  	@abc.abstractmethod
  	def buy_list_on(self,dt,bars,universe):
  		pass
  
  