How to install virtualbox on kali

#os Linux evankali 4.7.0-kali1-amd64 #1 SMP Debian 4.7.8-1kali1 (2016-10-24) x86_64 GNU/Linux

echo 'deb http://download.virtualbox.org/virtualbox/debian stretch contrib
' >> /etc/apt/sources.list

# combine downloading and registering:
wget -q https://www.virtualbox.org/download/oracle_vbox_2016.asc -O- | sudo apt-key add -
#or
wget -c https://www.virtualbox.org/download/oracle_vbox_2016.asc
sudo apt-key add oracle_vbox_2016.asc
apt-get update
apt-get install virtualbox-5.1

https://www.virtualbox.org/wiki/Linux_Downloads