from typing import Any

def group_by(items: list[dict[str, Any]], key: str) -> dict[str, list[dict[str, Any]]]:
    # Tu codigo aqui
    final = {}
    for dictionary in items:
        if dictionary[key] not in final:
            final[dictionary[key]] = [dictionary]
        else:
            final[dictionary[key]].append(dictionary)
    return final