Add comment detailing what many would find unreadbale

discord/flags.py

@@ -1567,6 +1567,14 @@ class ArrayFlags(BaseFlags):
     @classmethod
     def _from_value(cls: Type[Self], value: List[int]) -> Self:
         self = cls.__new__(cls)
+        # This is a micro-optimization given the frequency this object can be created.
+        # (1).__lshift__ is used in place of lambda x: 1 << x 
+        # prebinding to a method of a constant rather than define a lambda.
+        # Pairing this with map, is essentially equivalent to (1 << x for x in value)
+        # reduction using operator.or_ instead of defining a lambda each call
+        # Discord sends these starting with a value of 1
+        # Rather than subtract 1 from each element prior to left shift,
+        # we shift right by 1 once at the end.
         self.value = reduce(or_, map((1).__lshift__, value), 0) >> 1
         return self