在python中找不到要将文件作为附件发送的文件

import smtplib
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
from email.mime.application import MIMEApplication

def send_email_with_attachment(sender_email, sender_password, receiver_email, subject, body, attachment_path):
    # 创建邮件对象
    msg = MIMEMultipart()
    msg['From'] = sender_email
    msg['To'] = receiver_email
    msg['Subject'] = subject

    # 添加正文
    msg.attach(MIMEText(body, 'plain'))

    # 添加附件
    with open(attachment_path, 'rb') as file:
        attachment = MIMEApplication(file.read())
        attachment.add_header('Content-Disposition', 'attachment', filename=attachment_path)
        msg.attach(attachment)

    # 发送邮件
    with smtplib.SMTP('smtp.example.com', 587) as server:
        server.starttls()
        server.login(sender_email, sender_password)
        server.send_message(msg)

# 使用示例
sender_email = 'sender@example.com'
sender_password = 'password'
receiver_email = 'receiver@example.com'
subject = 'Email with Attachment'
body = 'Please find the attached file.'
attachment_path = 'path/to/file.txt'

send_email_with_attachment(sender_email, sender_password, receiver_email, subject, body, attachment_path)