forEach(func: T_MF): void {
    this.values.forEach((val, idx) => func(val, idx));
  }
forEach applied along the `Series` values

@param {function} func
 Function to apply along the values

@returns {Series}

@example
const ds = new Series([1, 2, 3, 4], {name: 'New Series'})

// Logs 1, 4, 9, 16
ds.forEach((val, idx) => console.log(val ** 2));