def METHOD_NAME(self, action, params=None, data="", headers=None, method="GET"):
    """Add the X-NFSN-Authentication header to an HTTP request."""
    if not headers:
        headers = {}
    if not params:
        params = {}
    header = self._header(action, data)
    headers["X-NFSN-Authentication"] = header
    if method == "POST":
        headers["Content-Type"] = "application/x-www-form-urlencoded"
    return ConnectionUserAndKey.METHOD_NAME(self, action, params, data, headers, method)