我正在尝试通过运行以下命令安装 sagemath：
sudo apt install sagemath
但它说：
Package sagemath is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source
我曾经通过这种方式安装 sagemath...有办法解决这个问题吗？
非常感谢