@classmethod
def class_name(cls):
    """Determine the class-name of the ColumnDefinition.

        If the column definition is part of FIDIA, then this is the bare class.
        If not, then it includes the module path to the class.

        """
    klass = cls.__module__ + '.' + cls.__name__
    if klass.startswith('fidia.'):
        klass = cls.__name__
    return klass
