code: public function &offsetGet($offset)
  	{
  		if (!$this->offsetExists($offset)) {
  			//	Be sure offset exists before accessing it.
  			$this->offsetSet($offset, null);
  
  			//	Returns new offset created by ::offsetSet().
  			if (null === $offset) {
  				end($this->_container);
  				$offset = key($this->_container);
  			}
  		}
  
  		return $this->_container[$offset];
  	}
docs: Required by the ArrayAccess interface.
  Returns reference to offset.
  
  http://stackoverflow.com/questions/20053269/indirect-modification-of-overloaded-element-of-splfixedarray-has-no-effect
  
  @param string|int $offset
  
  @return mixed