class not found when i am using Requests\CsvImportRequest

Error of class not found when i am passing parameter to function

error :

Class App\Http\Requests\CsvImportRequest does not exist

What should I for this error for my controller, I am pasting here what i done :

<?php
    namespace App\Http\Controllers\trades;

    use App\Contact;
    use App\CsvData;
    use App\Http\Requests\CsvImportRequest;
    use Illuminate\Http\Request;
    use Maatwebsite\Excel\Facades\Excel;
    use App\Http\Controllers\Controller;



    class ImportSingleTradesController extends Controller
    {

        public function tradesImport(CsvImportRequest $request)
        {
            $path = $request->file('csv_file')->getRealPath();
            if ($request->has('header')) {
                $data = Excel::load($path, function($reader) {})->get()->toArray();
            } else {
                $data = array_map('str_getcsv', file($path));
            }
            if (count($data) > 0) {
                if ($request->has('header')) {
                    $csv_header_fields = [];
                    foreach ($data[0] as $key => $value) {
                        $csv_header_fields[] = $key;
                    }
                }
                $csv_data = array_slice($data, 0, 2);
                $csv_data_file = CsvData::create([
                    'csv_filename' => $request->file('csv_file')->getClientOriginalName(),
                    'csv_header' => $request->has('header'),
                    'csv_data' => json_encode($data)
                ]);
            } else {
                return redirect()->back();
            }
            return view('member.add-single-trade.import-excel.import_fields', compact( 'csv_header_fields', 'csv_data', 'csv_data_file'));

        }

via Chebli Mohamed