(1.3.2.1) achievement conditions are clear

First of all, it is necessary for the achievement condition to be clear. "Studying" is unclear. "Mastering Ruby" is also unclear. You can not achieve it even if you spend much time. Then your heart breaks. For example of a clear condition, "build Ruby language from its source codes".

It is unclear if the condition 'understand the difference between Python lists and tuples' is unclear. It is because of the degree of "understand" is unclear. It's clear if the condition is "search and read about the differences between Python lists and tuples."