Indeed there is.  Apologies for tooting my own horn, but you can find it in [this paper][1], cowritten with Chris Koehl and Bill Spence.  Instead of repeating the explanation, I refer you to this [MathOverflow answer][2] from a decade ago.


  [1]: https://arxiv.org/abs/hep-th/9705161
  [2]: https://mathoverflow.net/a/16215/394