Fix for bug #222395: UTF-16 et al. don't handle .readline().
They now raise an NotImplementedError to hint to the truth ;-)
diff --git a/Lib/encodings/utf_16.py b/Lib/encodings/utf_16.py
index 72be072..2c2638f 100644
--- a/Lib/encodings/utf_16.py
+++ b/Lib/encodings/utf_16.py
@@ -53,6 +53,9 @@
             self.bom_read = 1
         return codecs.StreamReader.read(self, size)
 
+    def readline(self, size=None):
+        raise NotImplementedError, '.readline() is not implemented for UTF-16'
+
 ### encodings module API
 
 def getregentry():