docs: def send_email(msg, host='localhost', port=25,
           username=None, password=None):
      """
      Send an email (via TLS when username and password are specified)
  
      Parameters
      ----------
      msg : object
          An instance of MIMEText. Create this with :func:`create_message`
          function.
      host : string
          A mail user agent host name (Default: localhost)
      port : int
          A mail user agent port number (Default: 25)
      username : string
          A username string used to login MUA via TLS authentication
      password : string
          A password string used to login MUA via TLS authentication
      debug : boolean
          True for displaying debug messages
      """
      s = smtplib.SMTP(host, port)
      if username and password:
          s.ehlo()
          s.starttls()
          s.ehlo()
          s.login(user, passwd)
      s.sendmail(msg['From'], [msg['To']], msg.as_string())
      s.close()