Idioms and Anti-Idioms Question

[Ben Charrow]

I have a question about the "Using Backslash to Continue Statements" in the 
howto "Idioms and Anti-Idioms in Python" 
(http://docs.python.org/howto/doanddont.html#using-backslash-to-continue-statements) 


It says:

"...if the code was:

value = foo.bar()['first'][0]*baz.quux(1, 2)[5:9] \
         + calculate_number(10, 20)*forbulate(500, 360)

then it would just be subtly wrong."

What is subtly wrong about this piece of code?  I can't see any bugs and can't 
think of subtle gotchas (e.g. the '\' is removed or the lines become separated, 
because in both cases an IndentationError would be raised).

Cheers,
Ben