How does one use the tags option when creating resources with the aws cli?

Trying to create a tagged item with aws cli.

aws ec2 create-security-group --group-name $group_name --description $my_description

I can't parse the documentation

--tag-specifications (list)

I tried with

--tag-specifications KEY=Name,Value=$something

and --tags Key=Name,Value=$something
and --tags [Key=Name,Value=$something]
and --tags {[Key=Name,Value=$something]}