set_mail_class
Description:
Sets the mail_class property to mail_class.
Set mail_class to null to unset the property in the postal address.
Parameters:
| this | |
| mail_class | 
           the new mail class for the postal address, or   | 
      
Sets the mail_class property to mail_class.
Set mail_class to null to unset the property in the postal address.
| this | |
| mail_class | 
           the new mail class for the postal address, or   |