deb http://apt.llvm.org/focal/ llvm-toolchain-focal-9 main
deb-src http://apt.llvm.org/focal/ llvm-toolchain-focal-9 main
deb http://apt.llvm.org/focal/ llvm-toolchain-focal-10 main
deb-src http://apt.llvm.org/focal/ llvm-toolchain-focal-10 main