getValues() ). Including duplicates
* gives us an efficient way to distinguish zero attributes from non-zero
* but is not compliant with the spec, which states that duplicate
* attributes must be removed.
*
* @return integer
*/
public function count();
/**
* Add any attributes in the argument to $this, but if an attribute of the
* same name already exists, do not overwrite it.
*
* @param Attributes $other
*/
public function merge( Attributes $other );
}