Something wrong in calculations_atom_single.py

[Jy0417]

Hello! I'm writing to illustrate a problem in the package which will make it impossible to calculate AC-Stark Shift under the circumstances of sigma+ or sigma- light.
Line 3345 in your package calculations_atom_single.py should be (mjt - mjs == q) instead of (mjs - mjt == q). This error will make the function _findBasisStates unable to find any available states when q equals to 1 or -1, which will make the calculation of AC-Stark Shift only include the target state itself without considering any other states. Therefore the shifts are always zero. The (q == 0) situation is not affected by this problem.
Hope you can correct the little error soon!