stingray: A modern Python library for spectral timing. - Daniela Huppenkothen; Matteo Bachetti; Abigail Stevens; Simone Migliari; Paul Balm; Omar Hammad; Usman Mahmood Khan; Himanshu Mishra; Haroon Rashid; Swapnil Sharma; Evandro Martinez Ribeiro; Ricardo Vallés Blanco (J. Open Source Softw., 2019)