Traceback (most recent call last):
  File "/usr/portage/dev-lang/python/files/depreorder-topsort.py", line 32, in <module>
    realdeps = portage.dep_check(deps, fakedbapi, pkgsettings)
  File "/usr/lib/portage/pym/portage.py", line 3921, in dep_check
    use_binaries=use_binaries, myroot=myroot, trees=trees)
  File "/usr/lib/portage/pym/portage.py", line 3640, in _expand_new_virtuals
    portdb = trees[myroot]["porttree"].dbapi
TypeError: 'NoneType' object is unsubscriptable