[Ifeffit] Larch mback error report

Dear Larch developers (Matt), I believe I found an error in the mback function where I get a NameError saying the name ‘f1_chantler’ is not defined. I found that simply adding f1_chantler to the larch_plugins.xray import section in mback.py fixes the problem. I have included the modified mback.py code, my input data (SigScan226827.txt), project code (mback_test.py), and the error I received (mback_error.txt). I am running python 2.7 with anaconda as my manager, macOS Sierra v10.12, on a mid-2015 15” MacBook pro. I hope this report is correct and helpful. Regards, Sean Sean Fackler, PhD Joint Center for Artificial Photosynthesis Lawrence Berkeley National Lab 1 Cyclotron Rd Mail Stop 30R0205 Berkeley CA, 94720 Mobile: 609-613-8734