检查/etc/apt/sources.list.d/目录下是否有*python*.list文件，有则删除，可能是你之前安装python时添加过ppa。
删除之后执行：
sudo apt update && sudo apt install -f && sudo apt upgrade
不行则尝试：
sudo apt-get install gdb/bionic gir1.2-peas-1.0/bionic libpeas-1.0-0/bionic python3.6/bionic python3.6-minimal/bionic libpython3.6/bionic libpython3.6-minimal/bionic libpython3.6-stdlib/bionic
