Runtime Error

Error Message:
Runtime Error: Trying to dynamically access a method that does not exist throws a TypeError exception. To prevent the exception, ensure each parameter type matches those required by the 'QuantConnect.Resolution'>) method. Please checkout the API documentation.
  at OnSecuritiesChanged
    indicators['DM'] = self.dem(added.Symbol, 20, Resolution.Daily)

Below is the source code

if 'DM' in self.feature_list:
    indicators['DM'] = self.dem(added.Symbol, 20, Resolution.Daily)