code: def update_ttl new_ttl=nil
              # Load default if no new ttl is specified
              new_ttl = self._default_expire if new_ttl.nil?
              # Make sure we have a valid value
              new_ttl = -1 if !new_ttl.to_i.is_a?(Fixnum) || new_ttl.to_i < 0
              # Update indices
              Ohm.redis.expire(self.key, new_ttl)
              Ohm.redis.expire("#{self.key}:_indices", new_ttl)
          end
docs: Update the ttl
  
   ==== Attributes
  
   * +new_ttl <i>Fixnum</i>+ - The new expire amount. If nil, value will fallback to default expire
  
   ==== Returns
  
   * nil
  
   ==== Examples
  
     d = Model.create(:hash => "123")
     d.update_ttl(30)