<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_cdn_metadata(self, container):
 """ Returns a dictionary containing the CDN metadata for the container. If the container does not exist, a NotFound exception is raised. If the container exists, but is not CDN-enabled, a NotCDNEnabled exception is raised. """

        uri = "%s/%s" % (self.uri_base, utils.get_name(container))
        resp, resp_body = self.api.cdn_request(uri, "HEAD")
        ret = dict(resp.headers)
        # Remove non-CDN headers
        ret.pop("content-length", None)
        ret.pop("content-type", None)
        ret.pop("date", None)
        return ret