text: from flask_mail import Message
  from app import mail, app
  from flask import render_template
  from threading import Thread
  
  def send_async_email(app,msg):
      with app.app_context():
          mail.send(msg)
  
  def send_email(subject, sender, recipients, text_body, html_body):
      msg = Message(subject, sender=sender, recipients=recipients)
      msg.body = text_body
      msg.html = html_body
      Thread(target=send_async_email, args=(app, msg)).start()
      
  def send_password_reset_email(user):
      token = user.get_reset_password_token()
      send_email('[Microblog] Reset Your Password',
              sender=app.config['ADMINS'][0],
              recipients=[user.email],
              text_body=render_template('email/reset_password.txt', user=user, token=token),
              html_body=render_template('email/reset_password.html', user=user, token=token))