def METHOD_NAME(client, response):
    """Retrieve a list of mandates."""
    response.get(f"https://api.mollie.com/v2/customers/{CUSTOMER_ID}", "customer_single")
    response.get(f"https://api.mollie.com/v2/customers/{CUSTOMER_ID}/mandates", "customer_mandates_list")
    customer = client.customers.get(CUSTOMER_ID)
    mandates = customer.mandates.list()
    assert_list_object(mandates, Mandate)