How to use "bzr bisect"?

[Eli Zaretskii]

"bzr help bisect" falls short of telling to the uninitiated how to
begin the bisection process properly.

Suppose I have a tree at revision REVBUG which is known to exhibit a
bug.  Suppose I also know that a prior revision REVNOBUG does not
exhibit this bug.  How do I start the bisection?

What I did initially was ("yes" means "bug is present"):

  $ bzr bisect start
  $ bzr bisect yes

But it looks like the last command causes bisection between revision 1
and REVBUG.  That is, contrary to my expectations, "bzr bisect" did
not wait for me to specify both YES and NO revisions, before starting
the bisection.  Instead, it implicitly assumed that revision 1 has no
bug, and bisected between that and REVBUG.

Was I supposed to say "bzr bisect no -r REVNOBUG" before "bzr bisect
yes"?  Was I supposed to do something else?  Did I do something else
wrong?

TIA