How can I get waterpolo betting tips for a specific country using JavaScript?

I am a programmer looking to retrieve waterpolo betting tips for a specific country using JavaScript. I have found a resource that provides referees by country, but I am unsure how to use this information to get betting tips.

I have tried using the provided resource link with the country_id parameter, but I am not sure how to extract the betting tips data. I expected to receive a list of betting tips for the specified country, but I did not get the desired result.

const country_id = '123';
const url = `https://waterpolo.sportdevs.com/referees-by-country?country_id=eq.${country_id}`;

fetch(url)
  .then(response => response.json())
  .then(data => {
    console.log(data);
  })
  .catch(error => console.error('Error:', error));