docs: function findPivot(other) {
      var p1 = _path.call(this), p2 = _path.call(other), i, len, p;
  
      for (i = 0, len = p1.length < p2.length ? p1.length : p2.length; i < len; i++) {
        if (p1[i] === p2[i]) { p = p1[i]; } else { break; }
      }
  
      if (!p) {
        throw new Error('State#findPivot: states ' + this + ' and ' + other + ' do not belong to the same statechart');
      }
  
      return p;
    }