input: from typing import List
  
  def send_automated_emails(recipient_emails: List[str], sender_email: str, password: str) -> None:
      """ Sends an automated email to each address in the provided list of emails.
      This function iterates over the list of recipient emails and sends an email using
      the provided sender's email and password.
      >>> send_automated_emails(["email1@example.com","email2@example.com"], "example@gmail.com", "example_password")
      'Email sent successfully.'
      """
output:     import smtplib
      from email.mime.text import MIMEText
      from email.mime.multipart import MIMEMultipart
  
      for recipient in recipient_emails:
          msg = MIMEMultipart()
          msg['From'] = sender_email
          msg['To'] = recipient
          msg['Subject'] = "Automated Email"
  
          body = "This is an automated email sent to you."
          msg.attach(MIMEText(body, 'plain'))
  
          server = smtplib.SMTP('smtp.gmail.com', 587)
          server.starttls()
          server.login(sender_email, password)
          text = msg.as_string()
          server.sendmail(sender_email, recipient, text)
          server.quit()
  
      return 'Email sent successfully.'