code: function doesLoadBalancerExist (elb, loadBalancerName) {
    function inspectError (err) {
      if (err.code === 'LoadBalancerNotFound') {
        return false
      }
  
      return Bluebird.reject(err)
    }
  
    return elb
      .describeLoadBalancersPromised({
        LoadBalancerNames: [ loadBalancerName ]
      })
      .then(_.constant(true))
      .error(inspectError)
  }
docs: Uses the ELB.describeLoadBalancers method to check the existence of a load
  balancer. If the list of LoadBalancerDescriptions returned by the request
  is empty, doesLoadBalancerExist is resolved as False, if it's not empty it
  is resolved as True.
  
  @param elb
  @param loadBalancerName
  @returns {Promise}