diff -r a806ed21bd82 Lib/asyncio/selector_events.py
--- a/Lib/asyncio/selector_events.py	Fri Jan 15 02:18:31 2016 +0000
+++ b/Lib/asyncio/selector_events.py	Fri Jan 15 17:24:35 2016 +0100
@@ -682,8 +682,8 @@
 
     def write(self, data):
         if not isinstance(data, (bytes, bytearray, memoryview)):
-            raise TypeError('data argument must be byte-ish (%r)',
-                            type(data))
+            raise TypeError('data argument must be a bytes-like object, '
+                            'not %r' % type(data).__name__)
         if self._eof:
             raise RuntimeError('Cannot call write() after write_eof()')
         if not data:
@@ -954,8 +954,8 @@
 
     def write(self, data):
         if not isinstance(data, (bytes, bytearray, memoryview)):
-            raise TypeError('data argument must be byte-ish (%r)',
-                            type(data))
+            raise TypeError('data argument must be a bytes-like object, '
+                            'not %r' % type(data).__name__)
         if not data:
             return
 
@@ -1010,8 +1010,8 @@
 
     def sendto(self, data, addr=None):
         if not isinstance(data, (bytes, bytearray, memoryview)):
-            raise TypeError('data argument must be byte-ish (%r)',
-                            type(data))
+            raise TypeError('data argument must be a bytes-like object, '
+                            'not %r' % type(data).__name__)
         if not data:
             return