def futures_open_interest(self, **params):
"""Get present open interest of a specific symbol.
https://binance-docs.github.io/apidocs/futures/en/#open-interest-market_data
"""
return self._request_futures_api('get', 'ticker/openInterest', data=params)
the final line needs to be changed to
return self._request_futures_api('get', 'openInterest', data=params)