调用AmazonAPI会一直返回http 403错误

Question

我是Python的新手，正在尝试调用Amazon API：

from amazon.api import AmazonAPI

amazon = AmazonAPI(ac_key, sc_key, as_tag)

products = amazon.search(Keywords='kindle', SearchIndex='All')
for i, product in enumerate(products):
print "{0}. '{1}'".format(i, product.title)

但是，我一直收到这个错误。谁能帮我理解为什么？

    File
 "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/urllib2.py",
 line 558, in http_error_default
     raise HTTPError(req.get_full_url(), code, msg, hdrs, fp)
     urllib2.HTTPError: HTTP Error 403: Forbidden