class Thor

def task_help(shell, task_name)
  task = all_tasks[task_name]
  raise UndefinedTaskError, "task '#{task_name}' could not be found in namespace '#{self.namespace}'" unless task
  shell.say "Usage:"
  shell.say "  #{banner(task)}"
  shell.say
  class_options_help(shell, nil => task.options.map { |_, o| o })
  shell.say task.description
end