How to quickly produce a local datetime string in Haskell?

I'm looking for the best*est* way to produce the local time and date in string form, such as, for example:

"2009-09-28-00-44-36.896200000000"

I've been browsing Haskell's Data.Time docs, but I'm a bit stumped. (Big Haskell newbie here.)

Thanks!

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