'Displays the module, class and name of the field.'

def __repr__(self):

    path = (u'%s.%s' % (self.__class__.__module__, self.__class__.__name__))
    column_name = getattr(self, u'column_name', None)
    if (column_name is not None):
        return (u'<%s:    %s>' % (path, column_name))
    return (u'<%s>' % path)
