/**
* Property Begin Bind
*
* If no PHPExcel_Style_Protection has been bound to PHPExcel_Style then bind this one. Return the actual bound one.
*
* @return PHPExcel_Style_Protection
*/
private function propertyBeginBind() {
if(!isset($this->_parent))
return $this; // I am already bound
if($this->_parent->propertyIsBound($this->_parentPropertyName))
return $this->_parent->getProtection(); // Another one is already bound
$this->_parent->propertyCompleteBind($this, $this->_parentPropertyName); // Bind myself
$this->_parent = null;
return $this;
}