GetLastKnownPrices python data (#6191)

* Adding unit tests reproducing issue.

* Fix a couple of minor bugs

- IsMarketOpen will work correctly when used with daily and hourly
  resolution.
- slice.Get will work correctly with python custom data
- ExtendedDictionary will be able to dinamically access methods,
  required for python and private C# data types

* Refactor solution. Add more tests

* Remove unrequired import statement

Algorithm.Python/BasicTemplateFuturesDailyAlgorithm.py

@@ -50,6 +50,7 @@ class BasicTemplateFuturesDailyAlgorithm(QCAlgorithm):
                 front = sorted(contracts, key = lambda x: x.Expiry, reverse=True)[0]
 
                 self.contractSymbol = front.Symbol
-                self.MarketOrder(front.Symbol , 1)
+                if self.IsMarketOpen(self.contractSymbol):
+                    self.MarketOrder(front.Symbol , 1)
         else:
             self.Liquidate()