etcat -u php
[ Colour Code : set unset ]
[ Legend   : (U) Col 1 - Current USE flags        ]
[          : (I) Col 2 - Installed With USE flags ]
Traceback (most recent call last):
  File "/usr/bin/etcat", line 677, in ?
    main()
  File "/usr/bin/etcat", line 673, in main
    function(query, matches)
  File "/usr/bin/etcat", line 347, in uses
    if filter(gentoolkit.Package.is_installed, matches)
TypeError: unbound method is_installed() must be called with Package instance as first argument (got Package instance instead)