text: from abc import ABCMeta, abstractmethod
  
  class AbstractPortfolioAllocation(object):
  	"""
  	"""
  
  	__metaclass__ = ABCMeta
  
  	@abstractmethod
  	def calculate_weights(self):
  		"""
  		Provides the mechanisms to calculate the list of signals, suggested positional size, the strength of the signal
  		"""
  		raise NotImplementedError("Should implement calculate_weights()")