  Leaver's method has been the standard for computing the quasinormal mode
(QNM) frequencies for a Kerr black hole (BH) for a few decades. We start with a
spectral variant of Leaver's method introduced by Cook and Zalutskiy (arXiv:
1410.7698) and propose improvements in the form of computing the necessary
derivatives analytically, rather than by numerical finite differencing. We also
incorporate this derivative information into qnm, a Python package which finds
the QNM frequencies via the spectral variant of Leaver's method. We confine
ourselves to first derivatives only.
