[Python-ideas] Adding shallow argument in filecmp.dircmp

[Robert Vanden Eynde]

In module filecmp, the normal functions cmp and cmpfiles do have a
shallow attribute. But the dircmp class doesn't provide one, could we
add it in the constructor ?

In the implementation, it would only change the call to cmpfiles in def phase3 ?

It could be useful for performance (same reason, the "shallow"
parameter exists in the other two functions), when quickly comparing
two directories.