old_contents: import logging
  import json
  
  from flask import Flask,request,render_template,send_from_directory,redirect,url_for
  
  from google.appengine.ext import ndb
  from google.appengine.api import users
  
  from model import Match
  
  app = Flask(__name__, static_folder='static')
  app.config.update(dict(
      DEBUG=True,
      SECRET_KEY='f!>FTUEVvH7,%[yIjZUu79!9~k9nfi'
  ))
  app.config.from_envvar('FLASKR_SETTINGS', silent=True)
  
  # Note: We don't need to call run() since our application is embedded within
  # the App Engine WSGI application server.
  
  @app.route('/')
  def main():
      """Return a friendly HTTP greeting."""
      user = users.get_current_user()
      login_url = None
      user_nickname = None
      if not user:
          login_url = users.create_login_url(url_for('/'))
      else:
          user_nickname = user.nickname()
      return render_template('index.html', user_nickname=user_nickname, login_url=login_url)
  
  @app.errorhandler(404)
  def page_not_found(e):
      """Return a custom 404 error."""
      return 'Sorry, nothing at this URL.', 404
  
  if __name__ == '__main__':
      app.run()
new_contents: import logging
  import json
  
  from flask import Flask,request,render_template,send_from_directory,redirect,url_for
  
  from google.appengine.ext import ndb
  from google.appengine.api import users
  
  from model import Match
  
  app = Flask(__name__, static_folder='static')
  app.config.update(dict(
      DEBUG=True,
      SECRET_KEY='f!>FTUEVvH7,%[yIjZUu79!9~k9nfi'
  ))
  app.config.from_envvar('FLASKR_SETTINGS', silent=True)
  
  # Note: We don't need to call run() since our application is embedded within
  # the App Engine WSGI application server.
  
  @app.route('/')
  def main():
      """Return a friendly HTTP greeting."""
      user = users.get_current_user()
      login_url = None
      user_nickname = None
      if not user:
          login_url = users.create_login_url(url_for('main'))
      else:
          user_nickname = user.nickname()
      return render_template('index.html', user_nickname=user_nickname, login_url=login_url)
  
  @app.errorhandler(404)
  def page_not_found(e):
      """Return a custom 404 error."""
      return 'Sorry, nothing at this URL.', 404
  
  if __name__ == '__main__':
      app.run()
subject: fix url_for issue