    def __init__(self, event_source):
        """Create a new instance.

        Args:
            event_source: a source of events. Elements in the queue
            should be strings.
        """

        self.event_source = event_source
        self.subscribers = {}
Create a new instance.

Args:
event_source: a source of events. Elements in the queue
should be strings.
bigchaindb/web/websocket_server.py