tail(n: number = 5): Series {
    // $FlowFixMe TODO
    return this.iloc(this.length - n, this.length);
  }
Return last n rows

pandas equivalent: [Series.tail](http://pandas.pydata.org/pandas-docs/stable/generated/pandas.Series.tail.html)

@param {number} n=5
@returns {Series}

@example
const ds = new Series([1, 2, 3, 4, 5, 6, 7, 8]);

// Returns Series([4, 5, 6, 7, 8])
ds.tail();

// Returns Series([6, 7, 8])
ds.tail(3);