From fa769c0bc91cd794ec136eb5fb471a49fbb78773 Mon Sep 17 00:00:00 2001
From: Hagen Wierstorf <hwierstorf@audeering.com>
Date: Fri, 5 Aug 2022 12:18:18 +0200
Subject: [PATCH] Make Scheme.labels a property

---
 audformat/core/scheme.py | 25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/audformat/core/scheme.py b/audformat/core/scheme.py
index a041bf78..33d990e4 100644
--- a/audformat/core/scheme.py
+++ b/audformat/core/scheme.py
@@ -155,15 +155,30 @@ def __init__(
                     )
                 dtype = dtype_labels
 
-        self.dtype = dtype
-        r"""Data type"""
-        self.labels = labels
-        r"""List of labels"""
+        self._dtype = dtype
+        self._labels = labels
+
         self.minimum = minimum if self.is_numeric else None
         r"""Minimum value"""
         self.maximum = maximum if self.is_numeric else None
         r"""Maximum value"""
 
+    @property
+    def dtype(self) -> str:
+        r"""Data type"""
+        return self._dtype
+
+    @property
+    def labels(self) -> typing.Optional[typing.Union[dict, list, str]]:
+        r"""Labels of scheme"""
+        if (
+                self._labels is not None
+                and not isinstance(self._labels, str)
+        ):
+            return self._labels.copy()
+        else:
+            return self._labels
+
     @property
     def is_numeric(self) -> bool:
         r"""Check if data type is numeric.
@@ -327,7 +342,7 @@ def replace_labels(
                     f"'{dtype_labels}'"
                 )
 
-        self.labels = labels
+        self._labels = labels
 
         if self._db is not None and self._id is not None:
             labels = self._labels_to_list(labels)