# File lib/grape/middleware/versioner/param.rb, line 30
        def before
          potential_version = Rack::Utils.parse_nested_query(env[Grape::Http::Headers::QUERY_STRING])[paramkey]
          return if potential_version.nil?
          throw :error, status: 404, message: '404 API Version Not Found', headers: { Grape::Http::Headers::X_CASCADE => 'pass' } if options[:versions] && !options[:versions].find { |v| v.to_s == potential_version }
          env[Grape::Env::API_VERSION] = potential_version
          env[Grape::Env::RACK_REQUEST_QUERY_HASH].delete(paramkey) if env.key? Grape::Env::RACK_REQUEST_QUERY_HASH
        end