我需要有关以下错误的帮助。我正在使用 Ubuntu 18.04.4 LTS，并尝试安装 Ros melodic。我没有成功安装所有 ROS 包，也出现了此错误。
Check if you are using third party repositories. If so disable them, since they are a common source of problems.
Furthermore run the following command in a Terminal: apt-get install -f
Transaction failed: The package system is broken
The following packages have unmet dependencies:
python-rosdep-modules: Depends: python (>= 2.7) but 2.7.15~rc1-1 is installed
Depends: python:any (>= 2.6.6-7~) but it is a virtual package
Depends: python-rospkg-modules (>= 1.1.10) but it is not installed
python-rosdistro-modules: Depends: python (>= 2.7) but 2.7.15~rc1-1 is installed
Depends: python:any (>= 2.6.6-7~) but it is a virtual package
Depends: python-rospkg-modules but it is not installed