要解决"Autodesk Forge：下载清单附件"的问题，您可以使用以下代码示例：

1. 首先，您需要使用Forge API来获取清单中的附件列表。您可以使用以下代码示例：

import requests

# 设置您的Forge API凭据
client_id = 'YOUR_CLIENT_ID'
client_secret = 'YOUR_CLIENT_SECRET'

# 获取访问令牌
def get_access_token():
    url = 'https://developer.api.autodesk.com/authentication/v1/authenticate'
    data = {
        'client_id': client_id,
        'client_secret': client_secret,
        'grant_type': 'client_credentials',
        'scope': 'data:read bucket:read'
    }

    response = requests.post(url, data=data)
    access_token = response.json()['access_token']
    return access_token

# 获取清单中的附件
def get_attachments(manifest_urn):
    url = f'https://developer.api.autodesk.com/modelderivative/v2/designdata/{manifest_urn}/manifest'
    
    headers = {
        'Authorization': f'Bearer {get_access_token()}'
    }

    response = requests.get(url, headers=headers)
    attachments = response.json().get('derivatives', [])
    return attachments

# 使用示例
manifest_urn = 'YOUR_MANIFEST_URN'
attachments = get_attachments(manifest_urn)
print(attachments)

2. 获取附件列表后，您可以使用Forge API下载附件。以下是一个示例代码：

import requests

# 使用Forge API下载附件
def download_attachment(attachment_urn):
    url = f'https://developer.api.autodesk.com/modelderivative/v2/designdata/{attachment_urn}/download'
    
    headers = {
        'Authorization': f'Bearer {get_access_token()}'
    }

    response = requests.get(url, headers=headers)
    
    # 指定下载文件的保存路径和文件名
    save_path = 'YOUR_SAVE_PATH'
    file_name = 'YOUR_FILE_NAME'
    
    with open(f'{save_path}/{file_name}', 'wb') as file:
        file.write(response.content)

# 使用示例
attachment_urn = 'YOUR_ATTACHMENT_URN'
download_attachment(attachment_urn)

请注意，上述代码示例中的YOUR_CLIENT_ID、YOUR_CLIENT_SECRET、YOUR_MANIFEST_URN、YOUR_ATTACHMENT_URN、YOUR_SAVE_PATH和YOUR_FILE_NAME需要您自行替换为相应的值。