transition.tween API documentation missing a transition?

[myartsev]

Is the API sample for tween missing a call to transition?
A selection alone does not have a tween method.

selection.tween("attr.fill", function() {
  var node = this, i = d3.interpolateRgb(node.getAttribute("fill"), "blue");
  return function(t) {
    node.setAttribute("fill", i(t));
  };
});

selection.transition().tween("attr.fill", function() {
  var node = this, i = d3.interpolateRgb(node.getAttribute("fill"), "blue");
  return function(t) {
    node.setAttribute("fill", i(t));
  };
});

[mbostock]

I have corrected the README. Thank you for the report.