If one is essentially good and absolutely "KNOWS" it! Does one then have dark sides that need to be embraced? Certainly not!
There is an (alternative) thesis that says that everyone has dark sides. Consult yourself, are you a person who would allow evil into your life? No? Where are your dark sides then?
Don't be tempted by those who want to talk you into this. Those who believe in it are guided by their own assumed darkness. If they had deep insights about it, they would know that these are just illusions.
Eddy and Rita