input: Write a function to send an automated email to a list of recipients. The function should take a list of email addresses and use the SMTP protocol to send an email to each address. If the email is sent successfully, the function should print "Email sent successfully."
  
  def send_automated_email(recipient_emails):
      import smtplib
  
      sender_email = 'example@gmail.com'
      password = 'example_password'
  
      for email in recipient_emails:
          with smtplib.SMTP('smtp.gmail.com', 587) as server:
              server.ehlo()
              server.starttls()
              server.login(sender_email, password)
  
              subject = 'Automated Email from Program'
              message = 'Message body'
  
              server.sendmail(sender_email, email, 'Subject: ' + subject + '\n\n' + message)
              server.quit()
              print('Email sent successfully.')
  
  assert send_automated_email(["email1@example.com","email2@example.com"]) == None
output: def send_automated_email(recipient_emails):
      import smtplib
  
      sender_email = 'example@gmail.com'
      password = 'example_password'
  
      for email in recipient_emails:
          with smtplib.SMTP('smtp.gmail.com', 587) as server:
              server.ehlo()
              server.starttls()
              server.login(sender_email, password)
  
              subject = 'Automated Email from Program'
              message = 'Message body'
  
              server.sendmail(sender_email, email, 'Subject: ' + subject + '\n\n' + message)
              server.quit()
              print('Email sent successfully.')