May 8, 2018
I wrote this four years ago, so instead use this command:
$ docker rmi $(docker images -q -f dangling=true)
You'll want to login using an official Google account (i.e. if this is for your company, use the comapany Gmail account vs. a personal one.)
When logging in, you might be prompted to verify the account; if so, enter your cell number to get a verification e-mail or phone call.
Once verified, you'll have to agree to the terms of service; do that, and click continue.