export declare class Func {
    /**
     * Returns whether the given argument is not a function
     * @param  {Function} fn The argument to check
     * @return {boolean}     True if the given argument is not a function, otherwise false
     */
    static isNotAFunction(arg: any): boolean;
    /**
     * Returns whether the given argument is a function
     * @param  {Function} fn The argument to check
     * @return {boolean}     True if the given argument is a function, otherwise false
     */
    static isAFunction(arg: any): boolean;
}