bag_of_classes.py

class BagOfClass(type):
    class Value:
        pass

    def __iter__(klass):
        for attr_value in vars(klass).values():
            if isinstance(attr_value, type) and issubclass(
                attr_value, BagOfClass.Value
            ):
                yield attr_value


class Tables(metaclass=BagOfClass):
    class Table1(BagOfClass.Value):
        """documentation for first table"""

        NAME: str = "My First Table"
        COL11: str = "col11"
        COL12: str = "col12"
        COL13: str = "col13"

    class Table2(BagOfClass.Value):
        """documentation for second table"""

        NAME: str = "My Second table"
        COL21: str = "col21"
        COL22: str = "col22"
        COL23: str = "col23"


print(*[table.NAME for table in Tables])