diff --git a/src/escpos/constants.py b/src/escpos/constants.py
index f6bfcea..5328f4e 100644
--- a/src/escpos/constants.py
+++ b/src/escpos/constants.py
@@ -249,23 +249,26 @@ BARCODE_TYPE_B: Dict[str, bytes] = {
 
 #: supported barcode formats
 BARCODE_FORMATS = {
-    "UPC-A": ([(11, 12)], "^[0-9]{11,12}$"),
-    "UPC-E": ([(7, 8), (11, 12)], "^([0-9]{7,8}|[0-9]{11,12})$"),
-    "EAN13": ([(12, 13)], "^[0-9]{12,13}$"),
-    "EAN8": ([(7, 8)], "^[0-9]{7,8}$"),
-    "CODE39": ([(1, 255)], "^([0-9A-Z \$\%\+\-\.\/]+|\*[0-9A-Z \$\%\+\-\.\/]+\*)$"),
-    "ITF": ([(2, 255)], "^([0-9]{2})+$"),
-    "NW7": ([(1, 255)], "^[A-Da-d][0-9\$\+\-\.\/\:]+[A-Da-d]$"),
-    "CODABAR": ([(1, 255)], "^[A-Da-d][0-9\$\+\-\.\/\:]+[A-Da-d]$"),  # Same as NW7
-    "CODE93": ([(1, 255)], "^[\\x00-\\x7F]+$"),
-    "CODE128": ([(2, 255)], "^\{[A-C][\\x00-\\x7F]+$"),
-    "GS1-128": ([(2, 255)], "^\{[A-C][\\x00-\\x7F]+$"),  # same as CODE128
-    "GS1 DATABAR OMNIDIRECTIONAL": ([(13, 13)], "^[0-9]{13}$"),
-    "GS1 DATABAR TRUNCATED": ([(13, 13)], "^[0-9]{13}$"),  # same as GS1 omnidirectional
-    "GS1 DATABAR LIMITED": ([(13, 13)], "^[01][0-9]{12}$"),
+    "UPC-A": ([(11, 12)], r"^[0-9]{11,12}$"),
+    "UPC-E": ([(7, 8), (11, 12)], r"^([0-9]{7,8}|[0-9]{11,12})$"),
+    "EAN13": ([(12, 13)], r"^[0-9]{12,13}$"),
+    "EAN8": ([(7, 8)], r"^[0-9]{7,8}$"),
+    "CODE39": ([(1, 255)], r"^([0-9A-Z \$\%\+\-\.\/]+|\*[0-9A-Z \$\%\+\-\.\/]+\*)$"),
+    "ITF": ([(2, 255)], r"^([0-9]{2})+$"),
+    "NW7": ([(1, 255)], r"^[A-Da-d][0-9\$\+\-\.\/\:]+[A-Da-d]$"),
+    "CODABAR": ([(1, 255)], r"^[A-Da-d][0-9\$\+\-\.\/\:]+[A-Da-d]$"),  # Same as NW7
+    "CODE93": ([(1, 255)], r"^[\x00-\x7F]+$"),
+    "CODE128": ([(2, 255)], r"^\{[A-C][\x00-\x7F]+$"),
+    "GS1-128": ([(2, 255)], r"^\{[A-C][\x00-\x7F]+$"),  # same as CODE128
+    "GS1 DATABAR OMNIDIRECTIONAL": ([(13, 13)], r"^[0-9]{13}$"),
+    "GS1 DATABAR TRUNCATED": (
+        [(13, 13)],
+        r"^[0-9]{13}$",
+    ),  # same as GS1 omnidirectional
+    "GS1 DATABAR LIMITED": ([(13, 13)], r"^[01][0-9]{12}$"),
     "GS1 DATABAR EXPANDED": (
         [(2, 255)],
-        "^\([0-9][A-Za-z0-9 \!\"\%\&'\(\)\*\+\,\-\.\/\:\;\<\=\>\?\_\{]+$",
+        r"^\([0-9][A-Za-z0-9 \!\"\%\&'\(\)\*\+\,\-\.\/\:\;\<\=\>\?\_\{]+$",
     ),
 }