Modification of ReadonlyArray.groupBy Signature

export const groupBy: {
  <A>(f: (a: A) => string): (self: Iterable<A>) => Record<string, NonEmptyArray<A>>
  <A>(self: Iterable<A>, f: (a: A) => string): Record<string, NonEmptyArray<A>>
}

export const groupBy: {
  <A,K extends string>(f: (a: A) => K): (self: Iterable<A>) => Record<K, NonEmptyArray<A>>
  <A,K extends string>(self: Iterable<A>, f: (a: A) => K): Record<K, NonEmptyArray<A>>
}