bless $ref, [classname]
Looks up the item pointed to by reference ref and tells
the item that it is now
an object in the classname package - or the current package if no
classname
is specified. It returns the reference for
convenience, since a bless is often the last thing in a constructor
function. (Always use the two-argument version if the constructor doing
the blessing might be inherited by a derived class. In such cases,
the class you want to bless your object into will normally be found as the
first argument to the constructor in question.)