code: def shared_blockchain_instance(self):
          
          if not self._sharedInstance.instance:
              klass = self.get_instance_class()
              self._sharedInstance.instance = klass(**self._sharedInstance.config)
          return self._sharedInstance.instance
docs: This method will initialize ``SharedInstance.instance`` and return it.
              The purpose of this method is to have offer single default
              instance that can be reused by multiple classes.