py23 Add bytesjoin()
diff --git a/Lib/fontTools/ttLib/tables/otBase.py b/Lib/fontTools/ttLib/tables/otBase.py
index d43f156..72cbb3b 100644
--- a/Lib/fontTools/ttLib/tables/otBase.py
+++ b/Lib/fontTools/ttLib/tables/otBase.py
@@ -213,7 +213,7 @@
 			tableData = table.getData()
 			data.append(tableData)
 
-		return "".join(data)
+		return bytesjoin(data)
 	
 	def getDataLength(self):
 		"""Return the length of this table in bytes, without subtables."""
@@ -281,7 +281,7 @@
 						
 						raise OTLOffsetOverflowError(overflowErrorRecord)
 
-		return "".join(items)
+		return bytesjoin(items)
 	
 	def __hash__(self):
 		# only works after self._doneWriting() has been called