Command not found error mssqlctl and mssql-tools on ubuntu

When attempting to install the command line tools for SQL Server on Ubuntu 16.04.3, I would get the error: “E: Unable to locate package mssql-tools”

MSSQLCTL ERROR: written on python below are the steps to install.

1. Install the necessary Python packages:sudo apt-get update && / sudo apt-get install -y python3 && / sudo apt-get install -y python3-pip
2. Upgrade pip3:sudo -H pip3 install --upgrade pip
3. Install mssqlctl with the following command: pip3 install -r https://private-repo.microsoft.com/python/ctp-2.3/mssqlctl/requirements.txt --user

MSSQL-TOOLS ERROR : 

1. Import the public repository GPG keys used by apt to authenticate packages from Microsoft.
2. Add Microsoft to the apt repository.
3. Update the apt-get.
4. Install the mssql-tools now.