Class 'Importer' not found patosmack/laravel-excel - laravel-5

Actually I want to import an excel file to database using patosmack/laravel-excel library. I Followed all these steps given in this link but in the end I got this error. I don't know how to fix it. I searched this error every where no answer found.

from Newest questions tagged laravel-5 - Stack Overflow https://ift.tt/2MAK2ZX
via IFTTT