head(n: number = 5): Series {
    // $FlowFixMe TODO
    return this.iloc(0, n);
  }
Return first n rows

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

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

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

// Returns Series([1, 2, 3, 4, 5])
ds.head();

// Returns Series([1, 2, 3])
ds.head(3);