at(index) {
    return fromPaths(
      this.__paths.slice(
        index,
        index === -1 ? undefined : index + 1
      ),
      this
    );
  }
Returns a new collection containing only the element at position index.

In case of a negative index, the element is taken from the end:

  .at(0)  - first element
  .at(-1) - last element

@param {number} index
@return {Collection}