diff --git a/Lib/asyncio/proactor_events.py b/Lib/asyncio/proactor_events.py
index fef3205877f994..13a885cd559538 100644
--- a/Lib/asyncio/proactor_events.py
+++ b/Lib/asyncio/proactor_events.py
@@ -231,8 +231,9 @@ class _ProactorBaseWritePipeTransport(_ProactorBasePipeTransport,
 
     def write(self, data):
         if not isinstance(data, (bytes, bytearray, memoryview)):
-            raise TypeError('data argument must be byte-ish (%r)',
-                            type(data))
+            msg = ("data argument must be a bytes-like object, not '%s'" %
+                   type(data).__name__)
+            raise TypeError(msg)
         if self._eof_written:
             raise RuntimeError('write_eof() already called')