But users are supposed to run fits using the `Fitter.__call__` methods, so they need to know what the arguments are.
At the moment this doesn't appear in the html docs:
http://docs.astropy.org/en/latest/api/astropy.modeling.fitting.NonLinearLSQFitter.html

Did we decide to rename `__call__` to something else in this case?
I thought we did, but I can't find the issue right now, and for the 0.3.1 docs this should still be fixed, no?