Write a function resize(self, new_capacity: int) -> None that changes the capacity of the underlying storage for the elements in the dynamic array. It does not change the values or the order of any elements currently stored in the array. It is intended to be an "internal" method of the DynamicArray class, called by other class methods such as append(), remove_at_index(), or insert_at_index(), to manage the capacity of the underlying data structure. The method should only accept positive integers for new_capacity. Additionally, new_capacity cannot be smaller than the number of elements currently stored in the dynamic array (which is tracked by the self._size variable). If new_capacity is not a positive integer, or if new_capacity is less than self._size, this method should not do any work and immediately exit.