command line - mv: cannot stat ‘sources.list’: No such file or directory

I am trying to run the following command in my system after navigating to the directory cd /etc/apt

 Clean update:
cd /etc/apt
#out put stella@stella-box:/etc/apt$

sudo mv sources.list sources.list.ok


 #output mv: cannot stat ‘sources.list’: No such file or directory

#Recreate sources.list and add these 4 lines to it.
deb mirror://mirrors.ubuntu.com/mirrors.txt xenial main restricted 
universe multiverse 
deb mirror://mirrors.ubuntu.com/mirrors.txt xenial-updates main 
restricted universe multiverse 
deb mirror://mirrors.ubuntu.com/mirrors.txt xenial-backports main 
restricted universe multiverse 

deb mirror://mirrors.ubuntu.com/mirrors.txt xenial-security main 
restricted universe multiverse 


sudo apt-get clean 
sudo apt-get update
sudo apt install python3-pip
sudo apt-get install cmake  

I enter the next line it returns " mv: cannot stat ‘sources.list’: No such file or directory"
please guys how do I fixed this error?