input: Write a python function to send an email to a list of recipients using smtplib. 
  assert send_email(["john@example.com", "joe@example.com", "rob@example.com"]) == "Emails sent successfully"
  assert send_email(["alice@example.com"]) == "Emails sent successfully"
  assert send_email([]) == "No recipients provided"
output: def send_email(recipients):
      import smtplib
      from email.mime.text import MIMEText
      from email.mime.multipart import MIMEMultipart
  
      if not recipients:
          return "No recipients provided"
  
      sender_email = "youremail@example.com"
      sender_password = "yourpassword"
      subject = "Test Email"
      body = "This is a test email."
  
      msg = MIMEMultipart()
      msg['From'] = sender_email
      msg['Subject'] = subject
      msg.attach(MIMEText(body, 'plain'))
  
      try:
          server = smtplib.SMTP('smtp.example.com', 587)
          server.starttls()
          server.login(sender_email, sender_password)
  
          for recipient in recipients:
              msg['To'] = recipient
              server.sendmail(sender_email, recipient, msg.as_string())
  
          server.quit()
          return "Emails sent successfully"
      except Exception as e:
          print(f"Failed to send email: {e}")
          return "Failed to send email"