Parametrized quasinormal mode framework for non-Schwarzschild metrics

In this work we comment in more detail on what happens to the parametrized framework first presented by Cardoso et al. when there are departures from Schwarzschild background metric, as well possible deviations ``dynamics.'' We treat metric with additional coefficients respect original works. The advantages of reformulation clear applied a parameter estimation problem, since always real, and many them do not depend overtone number angular momentum frequency, thus eventually reducing total amount parameters be inferred.