Here's a simple pair of scripts, one is an applescript you turn into an application in /Applications, and the other is a shell script you put in /Users/Shared .
The applescript calls upon the shell script, and the result puts your computer to sleep within four seconds. You wake the computer by pressing any key on the keyboard. I prefer to use an arrow-key, like up-arrow or down-arrow. I probably could use the space-bar.
Download the two scripts, and move the "sleepnow" shell script into /Users/Shared. From Terminal.app, do these two commands:
cd /Users/Shared
chmod 755 sleepnow
That insures it can be executed. Then launch Script Editor or AppleScript Editor (either is in your /Applications/Utilities). Open "SleepNow.applescript", Duplicate it if necessary, and Compile it. Then, from the File menu, do "Save As..." or "Save". Then choose the Applications folder in the left panel, and Application or Application Bundle from File Format list. If available, check "Run Only" in Options, and "Hide Extension". Finally, click "Save".
Once you have SleepNow in /Applications, with "sleepnow" in /Users/Shared, any account on your system can use it. I made myself an Alias of the SleepNow application, and placed that alias on my Desktop. You could also "drag" SleepNow to your Dock. Either way, you have a handy way to sleep your computer. This works on every Mac-system I own, and it works with any keyboard.