I'm trying to access yesterday's high, low, close, etc...

def Initialize(self):

self.AddEquity("SPY")
self.test_high = ("SPY", 2, Resolution.Daily, Field.High)

def open_positions(self):

self.Log("test high")
self.Log(self.test_high[-1])

I get this log:

test high
System.Func`2[QuantConnect.Data.IBaseData,System.Decimal]

How do I get the decimal/value out of that object?