old_contents: from app import app, db
  from libforget.auth import require_auth_api, get_viewer
  from flask import jsonify, redirect, make_response, request
  from model import Account
  import libforget.settings
  import libforget.json
  
  @app.route('/api/health_check')
  def health_check():
      try:
          db.session.execute('SELECT 1')
          return 'ok'
      except Exception:
          return ('bad', 500)
  
  
  @app.route('/api/settings', methods=('PUT',))
  @require_auth_api
  def api_settings_put():
      viewer = get_viewer()
      data = request.json
      updated = dict()
      for key in libforget.settings.attrs:
          if key in data:
              if (
                      isinstance(getattr(viewer, key), bool) and
                      isinstance(data[key], str)):
                  data[key] = data[key] == 'true'
              setattr(viewer, key, data[key])
              updated[key] = data[key]
      db.session.commit()
      return jsonify(status='success', updated=updated)
  
  
  @app.route('/api/viewer')
  @require_auth_api
  def api_viewer():
      viewer = get_viewer()
      resp = make_response(libforget.json.account(viewer))
      resp.headers.set('content-type', 'application/json')
      return resp
  
  
  @app.route('/api/reason', methods={'DELETE'})
  @require_auth_api
  def delete_reason():
      get_viewer().reason = None
      db.session.commit()
      return jsonify(status='success')
  
  
  @app.route('/api/badge/users')
  def users_badge():
      count = (
          Account.query.filter(Account.policy_enabled)
          .filter(~Account.dormant)
          .count()
          )
      return redirect(
              "https://img.shields.io/badge/active%20users-{}-blue.svg"
              .format(count))
  
new_contents: from app import app, db
  from libforget.auth import require_auth_api, get_viewer
  from flask import jsonify, redirect, make_response, request, Response
  from model import Account
  import libforget.settings
  import libforget.json
  
  @app.route('/api/health_check')
  def health_check():
      try:
          db.session.execute('SELECT 1')
          return 'ok'
      except Exception:
          return ('bad', 500)
  
  
  @app.route('/api/settings', methods=('PUT',))
  @require_auth_api
  def api_settings_put():
      viewer = get_viewer()
      data = request.json
      updated = dict()
      for key in libforget.settings.attrs:
          if key in data:
              if (
                      isinstance(getattr(viewer, key), bool) and
                      isinstance(data[key], str)):
                  data[key] = data[key] == 'true'
              setattr(viewer, key, data[key])
              updated[key] = data[key]
      db.session.commit()
      return jsonify(status='success', updated=updated)
  
  
  @app.route('/api/viewer')
  @require_auth_api
  def api_viewer():
      viewer = get_viewer()
      resp = make_response(libforget.json.account(viewer))
      resp.headers.set('content-type', 'application/json')
      return resp
  
  
  @app.route('/api/reason', methods={'DELETE'})
  @require_auth_api
  def delete_reason():
      get_viewer().reason = None
      db.session.commit()
      return jsonify(status='success')
  
  
  @app.route('/api/badge/users')
  def users_badge():
      count = (
          Account.query.filter(Account.policy_enabled)
          .filter(~Account.dormant)
          .count()
          )
      return redirect(
              "https://img.shields.io/badge/active%20users-{}-blue.svg"
              .format(count))
  
  
  @app.route('/api/known_instances', methods=('GET', 'DELETE'))
  def known_instances():
      if request.method == 'GET':
          known = request.cookies.get('forget_known_instances', '')
          if not known:
              return Response('[]', 404, mimetype='application/json')
  
          return Response(known, mimetype='application/json')
  
      elif request.method == 'DELETE':
          resp = Response('', 204)
          resp.set_cookie('forget_known_instances', '', max_age=0)
          return resp
  
subject: add endpoint to access and clear existing known instances cookie