(PHP 5 >= 5.1.0, PHP 7) Return the inner iterator's children contained in a ParentIterator

(PHP 5 >= 5.1.0, PHP 7) Move the iterator forward

(PHP 5 >= 5.1.0, PHP 7) Rewind the iterator

(PHP 5 >= 5.1.0, PHP 7) Determines acceptability

(PHP 5 >= 5.1.0, PHP 7) Constructs a ParentIterator

(PHP 5 >= 5.1.0, PHP 7) Check whether the inner iterator's current element has children