Swagger Pass parameter to handler

I am using go-swagger, with a definition:

  /somethings:
    get:
      produces:
      - text/plain
      tags:
      - somethings
      summary: some summary
      operationId: GetSomethings
      responses:
        "200":
          description: some summary
          schema:
            type: string

I have a handler for this:

 package impl

 func GetSomethingsHandlerFunc(params metrics.GetSomethingsParams, namespace string) middleware.Responder {
     return middleware.ResponderFunc....
 }

GetSomethingsParams is autogenerated as:

type GetMetricsParams struct {

    // HTTP Request Object
    HTTPRequest *http.Request `json:"-"`
}

In configureAPI function:

api.SomethingsGetHandler = somethings.GetSomethingsHandlerFunc(impl.GetSomethingsHandlerFunc, "some_namespace_value")

How do I pass this namespace string (that is : "some_namespace_value") to the impl.GetSomethingsHandlerFunc?