sudo apt-get install python-pip

我收到以下错误

Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
 python-pip : Depends: python-setuptools (>= 0.6c1) but it is not going to be installed
              Recommends: python-dev-all (>= 2.6) but it is not installable
E: Unable to correct problems,you have held broken packages.

我已经安装了最新版本的python-dev

当我尝试使用安装python-setuptools时
sudo apt-get install python-setuptools我得到以下错误

Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
 python-setuptools : Depends: python-pkg-resources (= 3.3-1ubuntu1) but 3.3-1ubuntu2 is to be installed
E: Unable to correct problems,you have held broken packages.

解释我如何解决错误并指导我安装python-pip的步骤.