human
I wrote the below code

    def _send(retry):
        try:
            smtpserver = SMTPServer(append_to=append_to)
            email_body = email.as_string()
            smtpserver.sess.sendmail(email.sender, (email.recipients + (email.cc or [])), email_body)
        except smtplib.SMTPSenderRefused:
            frappe.throw(_(u'Invalid    login    or    password'), title=u'Email    Failed')
            raise
        except smtplib.SMTPRecipientsRefused:
            frappe.msgprint(_(u'Invalid    recipient    address'), title=u'Email    Failed')
            raise
        except (smtplib.SMTPServerDisconnected, smtplib.SMTPAuthenticationError):
            if (not retry):
                raise
            else:
                retry = (retry - 1)
                _send(retry)
    _send(retry)

What's a good function header?
 ... Here's a good function header?
assistant
#Here's a good function header.

def send(email, append_to=None, retry=1):