def traverse_enum(type_context, enum_proto, visitor):
    """Traverse an enum definition.

    Args:
        type_context: type_context.TypeContext for enum type.
        enum_proto: EnumDescriptorProto for enum.
        visitor: visitor.Visitor defining the business logic of the plugin.

    Returns:
        Plugin specific output.
    """
    return visitor.visit_enum(enum_proto, type_context)