code: function addReferences(descriptor) {
    _.forEach(descriptor, (desc, k) =>
      this.addReference(
        k,
        desc.target || desc.type,
        desc.cardinality,
        desc.opposite,
        desc.oppositeCardinality,
        desc.associated,
        desc.errorCallback,
        desc.oppositeErrorCallback)
      )
  }
docs: Add several references to the Class
  @method
  @memberof Class~ClassInstance
  @param {Object} descriptor - The definition of the attributes,
  the keys are the names of the attribute to create.
  The values contains the description of the attribute.
  See {@link Class~ClassInstance#addAttribute} parameters name
  for the supported property name.