lib/schema.js
function (name, validation) {
		if (name == null && validation == null) {
			this.isRequired = false;
			return this;
		}

		return this.field(name).validate(validation).optional();
	}
function (name, validation) {
		if (name == null && validation == null) {
			this.isRequired = false;
			return this;
		}

		return this.field(name).validate(validation).optional();
	}
function ( name , validation ) { if ( name == null && validation == null ) { this . isRequired = false ; return this ; } return this . field ( name ) . validate ( validation ) . optional ( ) ; }
add new optional nested schema by construct

@method
@this {Schema}
@param {?String} [name] - field name.
@param {?*} [validation] - validation options.
@returns {Schema}
add new optional nested schema by construct