Binary Tree Testing in "ape" package (a bug?)

Dear all,

I was testing the wonderful package APE.

However upon testing a particular Newick's format
tree - which I think to be a non-binary tree -
it yields different result as expected.

library(ape)
tree.hiv <- read.tree(text="(rat,mouse,(human,chimp));")
is.binary.tree(tree.hiv)

[1] TRUE

Was that a bug in APE package?

- Gundala Viswanath
Jakarta - Indonesia