/// <summary>
/// Gets all the user’s completed items (tasks).
/// </summary>
/// <param name="filter">The filter.</param>
/// <returns>The completed items.</returns>
/// <exception cref="HttpRequestException">API exception.</exception>
/// <remarks>Only available for Todoist Premium users.</remarks>
public Task <CompletedItemsInfo> GetCompletedAsync(ItemFilter filter = null)
{
var parameters = filter == null ? new List <KeyValuePair <string, string> >() : filter.ToParameters();
return(TodoistClient.PostAsync <CompletedItemsInfo>("completed/get_all", parameters));
}
