Docker Invalid Argument and format

I’m trying to connect Docker to a database that my professor set up for us so we can do our project but I’m getting errors and I have no idea why. This is the command the professor gave us:

docker build -t="<docker account name here>/lotterydb

So per his instructions, I open the command line in the folder where the database files for docker are located, then I use docker pull MySQL and then enter

docker build -t="<docker account name here>/lotterydb

And then this happens:

invalid argument "<sandrakm>/lotterydb" for "-t, --tag" flag: invalid reference format

I have Windows 10 and the newest docker version. And I change the docker account name to mine.

Source: Docker Questions