I want something like this:

```
class Fruits:
   APPLE = 'APPLE'
   ORANGE = 'ORANGE'
   MANGO = 'MANGO'

# I want to access members easily
print(Fruits.APPLE)

# I want to list all members
print(list(Fruits))

# I want to check if a string belongs to the set
print('POTATO' in Fruits)

```

I want plain string constants, grouped into a class with:

* member check
* listing all values

**Python enums do not seem to be suitable**, because:

* Enums are not plain strings, introduce a new type
* Enums require using `.value`
* Not directly serializable and are otherwise clumsy.

Is this implementable in Python? I suppose I might need some magic methods or metaclasses for this?