def instruments(self, filter=None):
    query = {}
    if (filter is not None):
        query['filter'] = json.dumps(filter)
    return self._curl_bitmex(path='instrument', query=query, verb='GET')
def instruments(self, filter=None):
    query = {}
    if (filter is not None):
        query['filter'] = json.dumps(filter)
    return self._curl_bitmex(path='instrument', query=query, verb='GET')