我无法在ubuntu 16.04上下载gem5

在尝试此命令之前，我甚至尝试了sudo apt get update，但它给出了相同的结果

问题在于我所在大学的一些代理设置。修复后问题得到解决，这是因为我所在大学的一些代理设置。解决了这个问题后就解决了

sudo apt-get install swig gcc m4 python python-dev libgoogle-perftools-dev mercurial scons g++ build-essential
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Package python-dev 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
However the following packages replace it:
  python

E: Unable to locate package swig
E: Unable to locate package m4
E: Package 'python-dev' has no installation candidate
E: Unable to locate package libgoogle-perftools-dev
E: Unable to locate package mercurial
E: Unable to locate package scons