Get Verification Count.  Uses HEAD to /verifications interface.

        :Returns: (int) Number of verifications

def verification_count(self):
        """
        Get Verification Count.  Uses HEAD to /verifications interface.

        :Returns: (int) Number of verifications
        """
        response = self._head(url.verifications)
        self._check_response(response, 200)
        return int(response.headers.get('x-verification-count', -1))