Functionality is continually added to ArcGIS Pro. When creating Python scripts taking advantage of new functionality, it is helpful to be able to check the version to either use an alternative method, or at least provide an error message informing the end user of needing to upgrade.
Fortunately, ArcPy provides a method to introspectively retrive ArcGIS Pro metadata, and among these properties is the current version as a string. From there, it is not a long script to compare the necessary version to the current version. Fortunately for you, if you need to figure this out, I have already created a short method to save you time. Enjoy!