input: Write a python function to send an email with a specified subject and body.
  assert send_email('recipient@example.com', 'Test Subject', 'Test Body')==None
  assert send_email('user@example.com', 'Greetings', 'Hello there!')==None
output: import smtplib
  from email.mime.text import MIMEText
  from email.mime.multipart import MIMEMultipart
  
  def send_email(recipient, subject, body):
      # Email configuration
      sender = 'youremail@example.com'
      password = 'yourpassword'
      
      # Create the email message
      msg = MIMEMultipart()
      msg['From'] = sender
      msg['To'] = recipient
      msg['Subject'] = subject
      msg.attach(MIMEText(body, 'plain'))
      
      # Send the email
      try:
          with smtplib.SMTP('smtp.example.com', 587) as server:
              server.starttls()
              server.login(sender, password)
              server.sendmail(sender, recipient, msg.as_string())
      except Exception as e:
          print(f"Failed to send email: {e}")