code: def iter_keys(self, number=-1, etag=None):
          
          url = self._build_url('keys', base_url=self._api)
          return self._iter(int(number), url, Key, etag=etag)
docs: Iterate over the public keys of this user.
  
          .. versionadded:: 0.5
  
          :param int number: (optional), number of keys to return. Default: -1
              returns all available keys
          :param str etag: (optional), ETag from a previous request to the same
              endpoint
          :returns: generator of :class:`Key <Key>`\ s