diff --git a/config/roles.php b/config/roles.php
index 9dcf575..2c1f515 100644
--- a/config/roles.php
+++ b/config/roles.php
@@ -13,7 +13,7 @@ return [
     'table_names' => [
         'permissions' => 'permissions',
         'permission_usage' => 'permission_usages',
-        'permission_member' => 'permission_member',
+        'permission_member' => 'permission_members',
         'roles' => 'roles',
         'role_member' => 'role_members',
         'role_permission' => 'role_permissions',
diff --git a/src/Traits/HasPermissions.php b/src/Traits/HasPermissions.php
index 5e2d6cb..fc94b21 100644
--- a/src/Traits/HasPermissions.php
+++ b/src/Traits/HasPermissions.php
@@ -47,7 +47,9 @@ trait HasPermissions
         if (is_numeric($permission)) {
             $permission = $permission_class::find($permission);
         } elseif (is_string($permission)) {
-            $permission = $permission_class::where('slug', $permission)->firstOrCreate();
+            $permission = $permission_class::firstOrCreate([
+                'slug' => $permission
+            ]);
         }
 
         if ($permission instanceof $permission_class) {
@@ -57,7 +59,9 @@ trait HasPermissions
         }
 
         if ($permission) {
-            return $this->permissions()->syncWithoutDetaching($permission);
+            $this->permissions()->syncWithoutDetaching($permission);
+
+            return true;
         }
 
         return false;
@@ -73,17 +77,13 @@ trait HasPermissions
             $permission = $permission_class::where('slug', $permission)->first();
         }
 
-        if ($permission instanceof $permission_class) {
-            // Already a Permission instance
-        } else {
-            throw new \InvalidArgumentException('Permission must be a string, numeric ID, or an instance of Permission.');
-        }
-
         if ($permission) {
-            return $this->permissions()->detach($permission);
+            $this->permissions()->detach($permission);
+
+            return true;
         }
 
-        return false;
+        return true;
     }
 
     /**