如何使用python更新github存储库中的现有文件，而不克隆存储库？

import requests

def update_file_on_github(repo_owner, repo_name, file_path, new_content, commit_message, access_token):
    # 构建API请求的URL
    url = f"https://api.github.com/repos/{repo_owner}/{repo_name}/contents/{file_path}"
    
    # 构建请求头部，包括授权信息
    headers = {
        "Authorization": f"Bearer {access_token}",
        "Accept": "application/vnd.github.v3+json"
    }
    
    # 发起GET请求获取文件信息
    response = requests.get(url, headers=headers)
    response_json = response.json()
    
    # 获取文件的SHA值和当前内容
    sha = response_json["sha"]
    current_content = response_json["content"]
    
    # 将新内容进行Base64编码
    import base64
    new_content_base64 = base64.b64encode(new_content.encode()).decode()
    
    # 如果新内容与当前内容相同，则无需更新
    if new_content_base64 == current_content:
        print("文件内容相同，无需更新")
        return
    
    # 构建更新文件的请求体
    data = {
        "message": commit_message,
        "content": new_content_base64,
        "sha": sha
    }
    
    # 发起PUT请求更新文件
    response = requests.put(url, json=data, headers=headers)
    
    if response.status_code == 200:
        print("文件更新成功")
    else:
        print("文件更新失败")

# 示例用法
repo_owner = "your_github_username"
repo_name = "your_repo_name"
file_path = "path/to/your_file.txt"
new_content = "This is the updated content."
commit_message = "Update file.txt"
access_token = "your_github_access_token"

update_file_on_github(repo_owner, repo_name, file_path, new_content, commit_message, access_token)