def addContact(self,id,name,phoneNr,group):
     """
         Add a new contact to the database
         id is the contact's id
         name is the contact's name
         phoneNr id the contact's phone number
         group is the contacts group
         raise ValueError if the contact is not valid
     """
     cr=ContactRepository()
     try:
         cr.add(Contact(id,name,phoneNr,group))
     except ValueError:
         return False