Task: My work has Finished now Logout my gmail id thomas.blac1978@gmail.com 
Steps:
Click on the back arrow key at the top left of the screen
Click on the back arrow key at the top left of the screen
Click on the profile icon at the top right of the screen
Click on the Manage accounts on this device option
Swipe down to find the thomas.blac1978@gmail.com
Click on the thomas.blac1978@gmail.com
Click on the Remove account button
Click on the Remove account at the pop up window