sub(other: any): Series {
    return this._combineOp(other, (a: number, b: number) => a - b, 'sub');
  }
Subtract another Iterable, `Series`, or number from the `Series`

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

@param {Iterable|Series|number} other
 Value to subtract from the `Series`

@returns {Series}

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

ds.sub(5)                           // Series([-4, -3, -2], {name: 'New Series'})
ds.sub(new Series([2, 3, 4]))       // Series([-1, -1, -1], {name: 'New Series'})
ds.sub([2, 3, 4])                   // Series([-1, -1, -1], {name: 'New Series'})
ds.sub(Immutable.List([2, 3, 4]))   // Series([-1, -1, -1], {name: 'New Series'})