+ (ENTRY SCORE [CLASS READ-ONLY])
+where the last two elements are optional.
+Possible values for CLASS are `?.' and '?,'. If CLASS is `?.', the
+entry takes a unique value which is overridden by newly assigned one
+by `lsdb-mode-edit-entry' or such a command. If CLASS is `?,', the
+entry can have multiple values separated by commas.
+If the fourth element READ-ONLY is non-nil, it is assumed that the
+entry cannot be modified."