Fatal Error Redeclaration Classes

I am getting sometimes:

PHP Fatal error: Cannot declare class Rest_Client_Abstract, because the name is already in use in wp-content/plugins/woocommerce-mercadopago/includes/module/sdk/lib/rest-client/class-rest-client-abstract.php on line 21

Code should be changed to:

 if (! class_exists('Rest_Client_Abstract') ) {
...
...
...
}

Same for:

PHP Fatal error: Cannot declare class MP_Rest_Client, because the name is already in use in wp-content/plugins/woocommerce-mercadopago/includes/module/sdk/lib/rest-client/class-mp-rest-client.php on line 19

if (! class_exists( 'MP_Rest_Client' ) ) {
...
...
...
}

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