# Table Mixins

It’s possible to create a mixin for a table that overrides something, however unless it itself is a subclass of `Table` class variable instances of `Column` will not be added to the class which is using the mixin.

Example:

    >>> class UselessMixin:
    ...     extra = tables.Column()
    ...
    >>> class TestTable(UselessMixin, tables.Table):
    ...     name = tables.Column()
    ...
    >>> TestTable.base_columns.keys()
    ["name"]

To have a mixin contribute a column, it needs to be a subclass of `Table`. With this in mind the previous example should have been written as follows:

    >>> class UsefulMixin(tables.Table):
    ...     extra = tables.Column()
    ...
    >>> class TestTable(UsefulMixin, tables.Table):
    ...     name = tables.Column()
    ...
    >>> TestTable.base_columns.keys()
    ["extra", "name"]