# File lib/doorkeeper/models/access_token_mixin.rb, line 131
    def generate_token
      self.created_at ||= Time.now.utc

      generator = Doorkeeper.configuration.access_token_generator.constantize
      self.token = generator.generate(
        resource_owner_id: resource_owner_id,
        scopes: scopes,
        application: application,
        expires_in: expires_in,
        created_at: created_at
      )
    rescue NoMethodError
      raise Errors::UnableToGenerateToken, "#{generator} does not respond to `.generate`."
    rescue NameError
      raise Errors::TokenGeneratorNotFound, "#{generator} not found"
    end