def destroy_keys attribute, *keys
      for key in keys
        new_value = send(attribute)
        new_value.delete(key.to_s)
        send("#{attribute}=", new_value)
      end
      self
    end
def destroy_keys attribute, *keys
      for key in keys
        new_value = send(attribute)
        new_value.delete(key.to_s)
        send("#{attribute}=", new_value)
      end
      self
    end
Deletes many keys in a record. E.g.
   witt = Person.find_by_name("Ludwig Wittgenstein")
   witt.destroy_keys(:info, :father, :mother)
 It does not save the record, so you'll have to do it.