code: public function getValue(string $mailableClass, string $argumentName, string $argumentType = '', $defaultValue = null)
      {
          if ($argumentType === 'int') {
              return $defaultValue ?? $this->faker->numberBetween(1, 100);
          }
  
          if ($argumentType === 'string') {
              return $defaultValue ?? $this->faker->sentence();
          }
  
          if ($argumentType === 'bool') {
              $defaultValue = ($defaultValue == 'false' ? false : $defaultValue);
  
              return $defaultValue ?? $this->faker->boolean(50);
          }
  
          try {
              $argumentValue = app($argumentType);
          } catch (Exception $exception) {
              throw CouldNotDetermineValue::create($argumentType, $argumentName, $exception);
          }
  
          if ($argumentValue instanceof Model) {
              return $this->getModelInstance($mailableClass, $argumentName, $argumentValue, $id = $defaultValue);
          }
  
          return $argumentValue;
      }
docs: @param string $mailableClass
  @param string $argumentName
  @param string $argumentType
  @param string|null $defaultValue
  
  @return mixed