Unable to set default python version to python3 in ubuntu

I was trying to set default python version to `python3` in `Ubuntu 16.04`. By default it is `python2` (2.7). I followed below steps : update-alternatives --remove python /usr/bin/python2 update-alternatives --install /usr/bin/python python /usr/bin/python3 but I'm getting the following error for the second statement, rejeesh@rejeesh-Vostro-1015:~$ update-alternatives --install /usr/bin/python python /usr/bin/python3 update-alternatives: --install needs <link> <name> <path> <priority> Use 'update-alternatives --help' for program usage information.