Fix typo

Doc/lib/libfuncs.tex

@@ -67,7 +67,7 @@ def my_import(name):
   user-defined or built-in function or method, or a class object) and
   the \var{args} argument must be a sequence.  The \var{function} is
   called with \var{args} as the argument list; the number of arguments
-  is the the length of the tuple.
+  is the length of the tuple.
   If the optional \var{keywords} argument is present, it must be a
   dictionary whose keys are strings.  It specifies keyword arguments
   to be added to the end of the the argument list.