code: function mconcatMap(m, f, xs) {
    if(!isMonoid(m)) {
      throw new TypeError(
        'mconcatMap: Monoid required for first argument'
      )
    }
  
    if(!isFunction(f)) {
      throw new TypeError(
        'mconcatMap: Function required for second argument'
      )
    }
  
    if(!isFoldable(xs)) {
      throw new TypeError(
        'mconcatMap: Foldable required for third argument'
      )
    }
  
    return _mconcatMap(m, f, xs)
  }
docs: mconcatMap : Monoid M => M -> (b -> a) -> ([ b ] | List b) -> M a