old_contents: from flask import Blueprint
  
  budget = Blueprint('budget', __name__, template_folder = 'templates')
  
  @budget.route('/')
  def default:
      return "Hello World!"
  
new_contents: from flask import Blueprint
  
  budget = Blueprint('budget', __name__, template_folder = 'templates')
  
  @budget.route('/')
  def default():
      return "Hello World!"
  
subject: Fix missing parenthesis for default route in budget module.