function groupByimport { groupBy } from "https://dotland.deno.dev/x/rambda@9.4.1/files/index.d.ts"; groupBy<T, K extends string = string>(fn: (a: T) => K): (list: T[]) => Partial<Record<K, T[]>>groupBy<T, K extends string = string>(fn: (a: T) => K, list: T[]): Partial<Record<K, T[]>>Type ParametersToptionalK extends string = stringParametersfn: (a: T) => KReturns(list: T[]) => Partial<Record<K, T[]>>Type ParametersToptionalK extends string = stringParametersfn: (a: T) => Klist: T[]ReturnsPartial<Record<K, T[]>>