MANGOPAY : Cannot redeclare _commerce_entity_theme_suggestions

I create a Gateway payment with Mangopay
When I clear the cache , i have the following error :

Fatal error: Cannot redeclare _commerce_entity_theme_suggestions() (previously declared in /home/.../www/letsrun/modules/commerce/commerce.module:156) in /home/.../www/letsrun/modules/contrib/commerce/commerce.module on line 156

My theme is BootStrap 3.0

ligne 156 of commerce.module

function _commerce_entity_theme_suggestions($entity_type_id, array $variables) {
$original = $variables['theme_hook_original'];
$entity = $variables['elements']['#' . $entity_type_id];
$sanitized_view_mode = strtr($variables['elements']['#view_mode'], '.', '_');

When i tried to add a product in a cart i have the following error :
The website encountered an unexpected error. Please try again later.

Error : Class 'Drupal\commerce_payment\PluginForm\PaymentMethodFormBase' not found dans include() (/home/..../www/letsrun/modules/commerce_mangopay_dpi/src/PluginForm/Onsite/PaymentMethodAddForm.php ligne 18) #0 /home/..../www/letsrun/vendor/composer/ClassLoader.php(444): include() #1 /home/..../www/letsrun/vendor/composer/ClassLoader.php(322): Composer\Autoload\includeFile('/home/mafuturin...') #2 [internal function]: Composer\Autoload\ClassLoader->loadClass('Drupal\\commerce...') #3 [internal function]: spl_autoload_call('Drupal\\commerce...') #4 /home/..../www/letsrun/core/lib/Drupal/Core/DependencyInjection/ClassResolver.php(23): class_exists('Drupal\\commerce...') #5 /home/..../www/letsrun/core/lib/Drupal/Core/Plugin/PluginFormFactory.php(52): Drupal\Core\DependencyInjection\ClassResolver->getInstanceFromDefinition('Drupal\\commerce...') #6 /home/..../www/letsrun/modules/contrib/commerce/modules/payment/src/Plugin/Commerce/InlineForm/PaymentGatewayForm.php(103): Drupal\Core\Plugin\PluginFormFactory->createInstance(Object(Drupal\commerce_mangopay_dpi\Plugin\Commerce\PaymentGateway\Mangopay), 'add-payment-met...') #7