Where to get type definitions for 'fetch' in TypeScript?

[Arsync]

The 'fetch' is not exists on Model.

For example, as it shown here in manuals:

await Comment.fetch('42'); // Unsafe call of an any typed value.
// or
await Comment.fetch({ id: '42' }); // Unsafe call of an any typed value.
// or
await Comment.dispatch('fetch', { filter: { id: '42' }}) // Ok, this one works.

we got 'Unsafe call of an any typed value' error.