I am trying to simply view a list of the symbols that are present in my universe each day, 15 minutes after market open. I have attached the code I have used below. For some reason whatever I do I am usually faced with the following error: "Runtime Error: TypeError : object is not callable TypeError : object is not callable". Any ideas on how to solve this?

class BasicTemplateFrameworkAlgorithm(QCAlgorithm):
def Initialize(self):

self.UniverseSettings.Resolution = Resolution.Daily

self.SetStartDate(2013,10,7) #Set Start Date
self.SetEndDate(2013,10,11) #Set End Date
self.SetCash(100000) #Set Strategy Cash

self.Schedule.On(self.DateRules.EveryDay("SPY"), self.TimeRules.AfterMarketOpen("SPY", 15), self.ViewUniverse)

def ViewUniverse(self):
for universe in self.UniverseManager.Values:
if universe is UserDefinedUniverse:
symbols = universe.Members.Keys
symbol_list = []

for symbol in symbols: