Fix bug/syntax in python examples (#8658)

* CustomDataRegressionAlgorithm

* DescendingCustomDataObjectStoreRegressionAlgorithm

* CustomDataPropertiesRegressionAlgorithm

* DateTime -> should be datetime

* KerasNeuralNetworkAlgorithm

* OptionIndicatorsMirrorContractsRegressionAlgorithm

* BybitCustomDataCryptoRegressionAlgorithm

* DropboxBaseDataUniverseSelectionAlgorithm

* UserDefinedUniverseAlgorithm

* CompleteOrderTagUpdateAlgorithm

* BasicTemplateOptionEquityStrategyAlgorithm hint

* ETFConstituentUniverseFrameworkRegressionAlgorithm

* FutureStopMarketOrderOnExtendedHoursRegressionAlgorithm

* SecurityDynamicPropertyPythonClassAlgorithm

* hint

* hinting

* CallbackCommandRegressionAlgorithm

* CustomWarmUpPeriodIndicatorAlgorithm

* CrunchDAOSignalExportDemonstrationAlgorithm

* ExpiryHelperAlphaModelFrameworkAlgorithm

* ClassicRenkoConsolidatorAlgorithm

* SmaCrossUniverseSelectionAlgorithm

* PEP8 Fix: Assigning to a Method

* SliceGetByTypeRegressionAlgorithm

* MarketOnCloseOrderBufferExtendedMarketHoursRegressionAlgorithm

* MarketOnCloseOrderBufferRegressionAlgorithm

* CustomIndicatorAlgorithm

* ScheduledQueuingAlgorithm

* ComboOrdersFillModelAlgorithm

* CustomIndicatorWithExtensionAlgorithm

* IndicatorWithRenkoBarsRegressionAlgorithm

* CoarseFineOptionUniverseChainRegressionAlgorithm

* NumeraiSignalExportDemonstrationAlgorithm

* DropboxUniverseSelectionAlgorithm

* WeeklyUniverseSelectionRegressionAlgorithm

* AutoRegressiveIntegratedMovingAverageRegressionAlgorithm

* DropboxBaseDataUniverseSelectionAlgorithm

* IronCondorStrategyAlgorithm

* LongAndShortButterflyPutStrategiesAlgorithm

* FutureStopMarketOrderOnExtendedHoursRegressionAlgorithm

* LongAndShortCallCalendarSpreadStrategiesAlgorithm

* KerasNeuralNetworkAlgorithm

* LongAndShortPutCalendarSpreadStrategiesAlgorithm

* OptionPriceModelForOptionStylesBaseRegressionAlgorithm

* TensorFlowNeuralNetworkAlgorithm

* MarketOnCloseOrderBufferRegressionAlgorithm

* MarketOnCloseOrderBufferExtendedMarketHoursRegressionAlgorithm

* typing

* ComboOrderTicketDemoAlgorithm

* PytorchNeuralNetworkAlgorithm

* MultipleSymbolConsolidationAlgorithm

* fixes

* revert getattr mypy syntax

* address peer review

* Addresses Peer-Review

---------

Co-authored-by: Alexandre Catarino <AlexCatarino@users.noreply.github.com>

Algorithm.Python/NumeraiSignalExportDemonstrationAlgorithm.py

@@ -23,9 +23,9 @@ from AlgorithmImports import *
 ### <meta name="tag" content="securities and portfolio" />
 class NumeraiSignalExportDemonstrationAlgorithm(QCAlgorithm):
 
-    securities = []
+    _securities = []
 
-    def initialize(self):
+    def initialize(self) -> None:
         ''' Initialize the date and add all equity symbols present in list _symbols '''
 
         self.set_start_date(2020, 10, 7)   #Set Start Date
@@ -63,9 +63,9 @@ class NumeraiSignalExportDemonstrationAlgorithm(QCAlgorithm):
         self.signal_export.add_signal_export_provider(NumeraiSignalExport(numerai_public_id, numerai_secret_id, numerai_model_id, numerai_filename))
 
 
-    def submit_signals(self):
+    def submit_signals(self) -> None:
         # Select the subset of ETF constituents we can trade
-        symbols = sorted([security.symbol for security in self.securities if security.has_data])
+        symbols = sorted([security.symbol for security in self._securities if security.has_data])
         if len(symbols) == 0:
             return
 
@@ -89,7 +89,7 @@ class NumeraiSignalExportDemonstrationAlgorithm(QCAlgorithm):
 
     def on_securities_changed(self, changes: SecurityChanges) -> None:
         for security in changes.removed_securities:
-            if security in self.securities:
-                self.securities.remove(security)
+            if security in self._securities:
+                self._securities.remove(security)
                 
-        self.securities.extend([security for security in changes.added_securities if security.symbol != self.etf_symbol])
+        self._securities.extend([security for security in changes.added_securities if security.symbol != self.etf_symbol])