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

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

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

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