I receive this error when I install the software.

Basically I want to know which space am I working on.

$sudo apt-get install indicator-workspaces

Reading package lists... Done

Building dependency tree       

Reading state information... Done

Package indicator-workspaces 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



E: Package 'indicator-workspaces' has no installation candidate