add a note about accessing user-defined functions with an import statement

in the setup parameter

Doc/lib/libtimeit.tex

@@ -193,3 +193,20 @@ missing and present object attributes.
 >>> print "%.2f usec/pass" % (1000000 * t.timeit(number=100000)/100000)
 3.15 usec/pass
 \end{verbatim}
+
+To give the \module{timeit} module access to functions you
+define, you can pass a \code{setup} parameter which contains an import
+statement:
+
+\begin{verbatim}
+def test():
+    "Stupid test function"
+    L = []
+    for i in range(100):
+        L.append(i)
+
+if __name__=='__main__':
+    from timeit import Timer
+    t = Timer("test()", "from __main__ import test")
+    print t.timeit()
+\end{verbatim}