Comment 2 for bug 2009829

Looks like you still have the Speedtest CLI app from Ookla's third party repo installed and it's conflicting with speedtest-cli from the Ubuntu repos. Uninstall the Ookla Speedtest CLI app first and see if that helps. Note that you may have to use dpkg manually at this point to fix things, probably by uninstalling the now likely half-installed speedtest-cli package. Then apt should start working normally again, and you can remove the conflicting app before trying to install speedtest-cli again.