# File lib/fog/aws/requests/rds/modify_db_instance.rb, line 47
        def modify_db_instance(db_name, apply_immediately, options={})
          response = Excon::Response.new
          if self.data[:servers][db_name]
            if self.data[:servers][db_name]["DBInstanceStatus"] != "available"
              raise Fog::AWS::RDS::NotFound.new("DBInstance #{db_name} not available for modification")
            else
              # TODO verify the params options
              # if apply_immediately is false, all the options go to pending_modified_values and then apply and clear after either 
              # a reboot or the maintainance window
              #if apply_immediately
              #  modified_server = server.merge(options)
              #else
              #  modified_server = server["PendingModifiedValues"].merge!(options) # it appends
              #end
              self.data[:servers][db_name]["PendingModifiedValues"].merge!(options) # it appends
              #self.data[:servers][db_name]["DBInstanceStatus"] = "modifying"
              response.status = 200
              response.body = {
                "ResponseMetadata"=>{ "RequestId"=> Fog::AWS::Mock.request_id },
                "ModifyDBInstanceResult" => { "DBInstance" => self.data[:servers][db_name] }
              }
              response
              
            end
          else
            raise Fog::AWS::RDS::NotFound.new("DBInstance #{db_name} not found")
          end
        end