Why not gathering all the enum values in the constructor instead of incrementally adding enum values

[wenjuno]

The enum implementation separates the creation of the enum type object and setting the enum values into two steps. The method of adding the enum modifies a whole bunch of private attributes to make it work. Why don't we ask for all the enum values in the constructor and build the whole class in one function call, just like how we would do in Python code? I feel this will make the code much simpler and isolated from implementation detail changes in Python.