def param?(name)
      _param = name.to_s =~ /^params./ ? name.to_s : 'params.' + name.to_s
      begin
        val = eval("self.#{_param}")
      rescue
        nil
      else
        val
      end
    end
def param?(name)
      _param = name.to_s =~ /^params./ ? name.to_s : 'params.' + name.to_s
      begin
        val = eval("self.#{_param}")
      rescue
        nil
      else
        val
      end
    end
Return value of param if it exists, nil otherwise.