How python is available without triggering installation?

If you execute python3 and it is not pointing to an active developer tools, the user is prompted to install the command-line tools. Is there a way to test if python3 is actually available without triggering installation?

(Our use case is that we would like to enumerate available python installs for the user to select from, without this accidentally triggering an install.)

How python is available without triggering installation?
 
 
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