Why executable not installed when ros package is installed through apt-get install?

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I was using teleop-twist package to control my robot till yesterday. Today when I tried to run the teleop-twist package, rosrun fails by showing no executable found inside the package. When I roscd to the package location, there is no teleop_twist_keyboard.py file. I removed the package using apt-get remove and re installed using apt-get install. Still python file is not present inside the package.