def method_missing(method, *args, &block) # :nodoc:
      case method.to_s
      when /^(.*)\?$/
        return !self.send($1.to_s).nil?
      when /^clear_(.*)$/
        self.send("#{$1.to_s}=", nil)
      else
        super
      end
    end
def method_missing(method, *args, &block) # :nodoc:
      case method.to_s
      when /^(.*)\?$/
        return !self.send($1.to_s).nil?
      when /^clear_(.*)$/
        self.send("#{$1.to_s}=", nil)
      else
        super
      end
    end
Responds to attribute query or attribute clear