How to use the react-leaflet.PropTypes function in react-leaflet

var React = require("react");
var Leaflet = require("leaflet");
var latlngType = require("react-leaflet").PropTypes.latlng;
var popupContainerMixin = require("react-leaflet").mixins.popupContainer;

var AppConstants = require('../constants/AppConstants');

function easeInOutCubic(t, b, c, d) {
    if ((t/=d/2) < 1) return c/2*t*t*t + b;
    return c/2*((t-=2)*t*t + 2) + b;
}

function animateMarker(marker, i, steps, startLatLng, deltaLatLng) {
    var x = easeInOutCubic(i, startLatLng[0], deltaLatLng[0], steps),
    y = easeInOutCubic(i, startLatLng[1], deltaLatLng[1], steps);

    marker.setLatLng([x, y]);

    if (i < steps) {

var React = require("react");
var Leaflet = require("leaflet");
var latlngType = require("react-leaflet").PropTypes.latlng;
var popupContainerMixin = require("react-leaflet").mixins.popupContainer;
require('leaflet.label');

function easeInOutCubic(t, b, c, d) {
    if ((t/=d/2) < 1) return c/2*t*t*t + b;
    return c/2*((t-=2)*t*t + 2) + b;
}

function animateMarker(marker, i, steps, startLatLng, deltaLatLng) {
    var x = easeInOutCubic(i, startLatLng[0], deltaLatLng[0], steps),
        y = easeInOutCubic(i, startLatLng[1], deltaLatLng[1], steps);

    marker.setLatLng([x, y]);

    if (i < steps) {
        Leaflet.Util.requestAnimFrame(animateMarker.bind(null, marker, i + 1, steps, startLatLng, deltaLatLng), null, false, marker._container);

var React = require("react");
var Leaflet = require("leaflet");
var latlngType = require("react-leaflet").PropTypes.latlng;
var popupContainerMixin = require("react-leaflet").mixins.popupContainer;
require('leaflet.label');

module.exports = React.createClass({
  displayName: "StopMarker",

  mixins: [popupContainerMixin],

  propTypes: {
    center: latlngType.isRequired,
    radius: React.PropTypes.number,
    label: React.PropTypes.string,
  },

  componentWillMount() {
    var {center, map, ...props} = this.props;