old_contents: from threading import Thread
  from flask import current_app, render_template
  from flask_mail import Message
  from . import mail
  
  
  def send_async_email(app, msg):
      with app.app_context():
          mail.send(msg)
  
  
  def send_email(to, subject, template, **kwargs):
      app = current_app._get_current_object()
      msg = Message('[' + current_app.config['SITE_NAME'] + '] ' + subject,
                    sender=current_app.config['MAIL_DEFAULT_SENDER'], recipients=[to])
      msg.body = render_template(template + '.txt', **kwargs)
      msg.html = render_template(template + '.html', **kwargs)
      thr = Thread(target=send_async_email, args=[app, msg])
      thr.start()
      return thr
  
new_contents: from flask import current_app, render_template
  from flask_mail import Message
  from . import mail
  
  
  def send_email(to, subject, template, **kwargs):
      msg = Message('[' + current_app.config['SITE_NAME'] + '] ' + subject,
                    sender=current_app.config['MAIL_DEFAULT_SENDER'], recipients=[to])
      msg.body = render_template(template + '.txt', **kwargs)
      msg.html = render_template(template + '.html', **kwargs)
      mail.send(msg)
  
subject: Remove threads from email