def changes_in(self, rev_or_range):
    """
    :API: public
    """
    try:
      return self._scm.changes_in(rev_or_range, relative_to=get_buildroot())
    except Scm.ScmException as e:
      raise self.WorkspaceError("Problem detecting changes in {}.".format(rev_or_range), e)
:API: public