def get_proxy_version(self):
        """
        
        """
        self._download_sql_proxy_if_needed()
        command_to_run = [self.sql_proxy_path]
        command_to_run.extend(['--version'])
        command_to_run.extend(self._get_credential_parameters())
        result = subprocess.check_output(command_to_run).decode('utf-8')
        pattern = re.compile("^.*[V|v]ersion ([^;]*);.*$")
        m = pattern.match(result)
        if m:
            return m.group(1)
        else:
            return None