default Optional<? extends Column> findColumn() {
        return ancestors()
            .filter(Table.class::isInstance)
            .map(Table.class::cast)
            .findFirst()
            .flatMap(table -> table
                .columns()
                .filter(col -> col.getId().equals(getId()))
                .findAny()
            );
    }
Locates and returns the column referenced by the {@link #getId()} 
method.
<p>
The column must reside as a child to the table that is
an ancestor (i.g. a parent or a parent of a parent...) to this
Document.

@return  the referenced column
runtime-parent/runtime-config/src/main/java/com/speedment/runtime/config/trait/HasColumn.java