In Python, there are conventions for single leading underscore, double leading underscore, double leading + double trailing underscore, and single trailing underscore. Many of those are outlined in the answers at What is the meaning of a single- and a double-underscore before an object name?. But what is the meaning or convention for single leading + single trailing underscore? I've first seen their use in the enum module: 8.13.15.3.2. Supported _sunder_ names _name_ – name of the member _value_ – value of the member; can be set / modified in new _missing_ – a lookup function used when a value is not found; may be overridden _ignore_ – a list of names, either as a list() or a str(), that will not be transformed into members, and will be removed from the final class _order_ – used in Python 2/3 code to ensure member order is consistent (class attribute, removed during class creation) _generate_next_value_ – used by the Functional API and by auto to get an appropriate value for an enum member; may be overridden I have not seen such single-leading-single-trailing underscore sunder names before. Are they treated in any special way, or otherwise have an implied meaning that is distinct from any of the other underscore-related naming conventions? How are they different from having no underscores at all? Continue reading...
