E: Could not get lock /var/lib/dpkg/lock-frontend. code example

Example 1: Unable to acquire the dpkg frontend lock (/var/lib/dpkg/lock-frontend), is another process using it?

ps aux | grep -i dpkg

// Kill processes which are running
sudo kill -9 

// Restart the accounts daemon
sudo systemctl restart accounts-daemon

Example 2: Could not get lock /var/lib/dpkg/lock-frontend - open (11: Resource temporarily unavailable)

Method 1
ps aux | grep -i apt
sudo kill -9 

Method 2

sudo lsof /var/lib/dpkg/lock
sudo lsof /var/lib/apt/lists/lock
sudo lsof /var/cache/apt/archives/lock

sudo kill -9 

sudo rm /var/lib/apt/lists/lock
sudo rm /var/cache/apt/archives/lock
sudo rm /var/lib/dpkg/lock

sudo dpkg --configure -a

sudo apt update