make __import__ 4-args
diff --git a/Doc/libimp.tex b/Doc/libimp.tex
index 1ee7ced..1a313fa 100644
--- a/Doc/libimp.tex
+++ b/Doc/libimp.tex
@@ -135,7 +135,7 @@
 import imp
 from sys import modules
 
-def __import__(name):
+def __import__(name, globals=None, locals=None, fromlist=None):
     # Fast path: let's see if it's already in sys.modules.
     # Two speed optimizations are worth mentioning:
     # - We use 'modules' instead of 'sys.modules'; this saves a