old_contents: import flask
  from pyshelf.routes.artifact import artifact
  import pyshelf.response_map as response_map
  
  app = flask.Flask(__name__)
  app.register_blueprint(artifact)
  
  @app.errorhandler(Exception)
  def generic_exception_handler(error):
      return response_map.create_500(msg=error.message)
  
  @app.after_request
  def format_response(response):
      if response.status_code == 404:
          response = response_map.create_404()
  
      data = response.get_data()
      data += "\n"
      response.set_data(data)
      return response
  
new_contents: import flask
  from pyshelf.routes.artifact import artifact
  import pyshelf.response_map as response_map
  
  app = flask.Flask(__name__)
  app.register_blueprint(artifact)
  
  @app.errorhandler(Exception)
  def generic_exception_handler(error):
      if not error.message:
          error.message = "Internal Server Error"
      return response_map.create_500(msg=error.message)
  
  @app.after_request
  def format_response(response):
      if response.status_code == 404:
          response = response_map.create_404()
  
      data = response.get_data()
      data += "\n"
      response.set_data(data)
      return response
  
subject: Add default message.