--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/env/lib/python3.9/site-packages/rdflib/events.py	Mon Mar 22 18:12:50 2021 +0000
@@ -0,0 +1,97 @@
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+__doc__ = """
+Dirt Simple Events
+
+A Dispatcher (or a subclass of Dispatcher) stores event handlers that
+are 'fired' simple event objects when interesting things happen.
+
+Create a dispatcher:
+
+  >>> d = Dispatcher()
+
+Now create a handler for the event and subscribe it to the dispatcher
+to handle Event events.  A handler is a simple function or method that
+accepts the event as an argument:
+
+  >>> def handler1(event): print(repr(event))
+  >>> d.subscribe(Event, handler1)
+
+Now dispatch a new event into the dispatcher, and see handler1 get
+fired:
+
+  >>> d.dispatch(Event(foo='bar', data='yours', used_by='the event handlers'))
+  <rdflib.events.Event ['data', 'foo', 'used_by']>
+"""
+
+__all__ = ['Event', 'Dispatcher']
+
+
+class Event(object):
+    """
+    An event is a container for attributes.  The source of an event
+    creates this object, or a subclass, gives it any kind of data that
+    the events handlers need to handle the event, and then calls
+    notify(event).
+
+    The target of an event registers a function to handle the event it
+    is interested with subscribe().  When a sources calls
+    notify(event), each subscriber to that event will be called in no
+    particular order.
+    """
+
+    def __init__(self, **kw):
+        self.__dict__.update(kw)
+
+    def __repr__(self):
+        attrs = sorted(self.__dict__.keys())
+        return '<rdflib.events.Event %s>' % ([a for a in attrs],)
+
+
+class Dispatcher(object):
+    """
+    An object that can dispatch events to a privately managed group of
+    subscribers.
+    """
+
+    _dispatch_map = None
+
+    def set_map(self, amap):
+        self._dispatch_map = amap
+
+    def get_map(self):
+        return self._dispatch_map
+
+    def subscribe(self, event_type, handler):
+        """ Subscribe the given handler to an event_type.  Handlers
+        are called in the order they are subscribed.
+        """
+        if self._dispatch_map is None:
+            self.set_map({})
+        lst = self._dispatch_map.get(event_type, None)
+        if lst is None:
+            lst = [handler]
+        else:
+            lst.append(handler)
+        self._dispatch_map[event_type] = lst
+
+    def dispatch(self, event):
+        """ Dispatch the given event to the subscribed handlers for
+        the event's type"""
+        if self._dispatch_map is not None:
+            lst = self._dispatch_map.get(type(event), None)
+            if lst is None:
+                raise ValueError("unknown event type: %s" % type(event))
+            for l in lst:
+                l(event)
+
+
+def test():
+    import doctest
+    doctest.testmod()
+
+
+if __name__ == '__main__':
+    test()