src/precore/util/FluentIterable.php
public function append(IteratorAggregate $other) : FluentIterable
    {
        return self::from(Iterables::concat($this, $other));
    }
public function append(IteratorAggregate $other) : FluentIterable
    {
        return self::from(Iterables::concat($this, $other));
    }
Returns a fluent iterable whose iterators traverse first the elements
of this fluent iterable, followed by those of other.

@param IteratorAggregate $other
@return FluentIterable