import random

class StockMarket(object):
    def __init__(self, marketname, symbols):
        self.name=marketname
        self.symbolmeans={}
        for symbol in symbols:
            self.symbolmeans[symbol]=random.uniform(20,200)
        self.aggregators=[]

    def generate(self):
        quotes={}
        for symbol,mean in self.symbolmeans.items():
            if random.random()<0.2:
                quotes[symbol]=round(random.normalvariate(mean,20),2)
        for aggregator in self.aggregators:
            aggregator.quotes(self.name, quotes)

    def listener(self,aggregator):
        self.aggregators.append(aggregator)

    def symbols(self):
        return self.symbolmeans.keys()