$this->faker->boolean(80) ? $this->faker->unique()->numerify('######') : null, 'title' => $this->faker->sentence(3), 'author' => $this->faker->name(), 'copyright_text' => $this->faker->optional()->sentence(), 'copyright_year' => (string) $this->faker->year(), 'publisher' => $this->faker->optional()->company(), 'has_translation' => $this->faker->boolean(25), 'last_used_at' => $this->faker->optional()->dateTimeBetween('-6 months', 'now'), ]; } }