Trivial typo
diff --git a/Doc/library/asyncio-stream.rst b/Doc/library/asyncio-stream.rst
index 9fcea88..fa076df 100644
--- a/Doc/library/asyncio-stream.rst
+++ b/Doc/library/asyncio-stream.rst
@@ -223,7 +223,7 @@
.. class:: StreamReaderProtocol(stream_reader, client_connected_cb=None, loop=None)
Trivial helper class to adapt between :class:`Protocol` and
- :class:`StreamReader`. Sublclass of :class:`Protocol`.
+ :class:`StreamReader`. Subclass of :class:`Protocol`.
*stream_reader* is a :class:`StreamReader` instance, *client_connected_cb*
is an optional function called with (stream_reader, stream_writer) when a