import json


def get_currencies(meli):
    """
    Retrieve currencies from https://api.mercadolibre.com/currencies
    """
    listing_types = list()
    
    response = meli.get('/currencies/')
    json_response = json.loads(response.content)
    
    for listing_type in json_response:
        listing_types.append((listing_type['id'], listing_type['description']))
    return listing_types