_createMethod(methodDef, name) {
		let method;
		if (isFunction(methodDef)) {
			// Wrap to an object
			method = {
				handler: methodDef
			};
		} else if (isObject(methodDef)) {
			method = methodDef;
		} else {
			throw new ServiceSchemaError(
				`Invalid method definition in '${name}' method in '${this.fullName}' service!`
			);
		}

		if (!isFunction(method.handler)) {
			throw new ServiceSchemaError(
				`Missing method handler on '${name}' method in '${this.fullName}' service!`
			);
		}

		method.name = name;
		method.service = this;
		method.handler = method.handler.bind(this);

		this[name] = this.broker.middlewares.wrapHandler("localMethod", method.handler, method);

		return method;
	}
Create an internal service method.

@param {Object|Function} methodDef
@param {String} name
@returns {Object}