We're using the company endpoint to get emails for one domain.
You pass in the domain, then pass in your API key (which you get from your account settings) as a header.
data = {'domain': domain}
headers = {'X-Api-Key': 'yourApiKey'}
resp = requests.post('https://api.anymailfinder.com/v4.0/search/company.json', data=data, headers=headers)
data = json.loads(resp.content)
Remember, it's a POST request!
You can begin with the API docs here: https://anymailfinder.com/api/
If you want, test the API in the www.getpostman.com app first. It's a good app :)