filterAndFlat (options, search, label) {
      return flow(
        this.filterGroups(search, label, this.groupValues, this.groupLabel, this.customLabel),
        flattenOptions(this.groupValues, this.groupLabel)
      )(options)
    }
Filters and then flattens the options list
@param  {Array}
@return {Array} returns a filtered and flat options list