How to use the prosodic.lib.entity.being.pointsofcomparison function in prosodic

if self.classname()!="Corpus":
			return "<< cannot groom object smaller than corpus: grooming meant to normalize corpus of texts to a standard >>"
		
		
		textdict={}
		text2lines={}
		for text in self.children:
			validlines=text.validlines()
			textdict[text]=str(len(validlines))+" lines"
			text2lines[text]=validlines
		
		sels=choose(textdict,"please select the primary text whose attributes will be sought after in the others:")
		primary=sels[0]
		
		sels=choose(['wordbound','stress','weight'],"please choose the dimensions on which lines of primary text <"+repr(primary)+"> must be matched:")
		being.pointsofcomparison=[]
		for sel in sels:
			being.pointsofcomparison.append("str_"+sel.strip())
		
		sels=choose({'difference':'remove non-matching lines in non-primary texts only','intersection':'remove non-matching lines in all texts'},"please select method of grooming:")
		diffmethod=sels[0]
		
		#if diffmethod=="intersection":
		#	
		
		# lineset=set(text2lines[primary])
		# 		if diffmethod=="intersection":
		# 			for text in self.children:
		# 				thislineset=set(text2lines[text])
		# 				for line in (lineset ^ thislineset):
		# 					line.ignoreMe=True
		# 				

if self.classname()!="Corpus":
			return "<< cannot groom object smaller than corpus: grooming meant to normalize corpus of texts to a standard >>"


		textdict={}
		text2lines={}
		for text in self.children:
			validlines=text.validlines()
			textdict[text]=str(len(validlines))+" lines"
			text2lines[text]=validlines

		sels=choose(textdict,"please select the primary text whose attributes will be sought after in the others:")
		primary=sels[0]

		sels=choose(['wordbound','stress','weight'],"please choose the dimensions on which lines of primary text <"+repr(primary)+"> must be matched:")
		being.pointsofcomparison=[]
		for sel in sels:
			being.pointsofcomparison.append("str_"+sel.strip())

		sels=choose({'difference':'remove non-matching lines in non-primary texts only','intersection':'remove non-matching lines in all texts'},"please select method of grooming:")
		diffmethod=sels[0]

		#if diffmethod=="intersection":
		#

		# lineset=set(text2lines[primary])
		# 		if diffmethod=="intersection":
		# 			for text in self.children:
		# 				thislineset=set(text2lines[text])
		# 				for line in (lineset ^ thislineset):
		# 					line.ignoreMe=True
		#