How to install ros-electric-object-recognition?

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I use ROS electric.

I followed Object Recognition Kitchen.

This doc says 'Install the ros-electric-object-recognition package from the official ROS repositories.'

I try to install:

  sam@/home/sam$ sudo apt-get install ros-electric-object-recognition
  Reading package lists... Done
  Building dependency tree       
  Reading state information... Done
  E: Unable to locate package ros-electric-object-recognition

  sam@/home/sam$

How to fix it?

Thank you~

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ROS apt:

  sam@/etc/apt/sources.list.d$ cat ros-latest.list
  # deb http://packages.ros.org/ros/ubuntu natty main # 停用升級至 natty

  sam@/etc/apt/sources.list.d$ cat ros-latest.list.distUpgrade 
  deb http://packages.ros.org/ros/ubuntu maverick main

  sam@/etc/apt/sources.list.d$ cat ros-latest.list.save 
  deb http://packages.ros.org/ros/ubuntu maverick main

  sam@/etc/apt/sources.list.d$