diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index cb0e0e7..faf72b0 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -19,13 +19,20 @@ jobs:
         - python-version: "3.10"
           env:
             TOXENV: py
-        - python-version: "3.10"
+        - python-version: "3.11"
+          env:
+            TOXENV: py
+        - python-version: "3.12"
+          env:
+            TOXENV: py
+        - python-version: "3.13"
+          env:
+            TOXENV: py
+        - python-version: "3.13"
           env:
             TOXENV: mypy
-
     steps:
     - uses: actions/checkout@v3
-
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v4
       with:
diff --git a/price_parser/parser.py b/price_parser/parser.py
index 0a0f8ba..5f193d1 100644
--- a/price_parser/parser.py
+++ b/price_parser/parser.py
@@ -56,8 +56,8 @@ def fromstring(
         currency = extract_currency_symbol(price, currency_hint)
         if currency is not None:
             currency = currency.strip()
-        if digit_group_separator and price is not None:
-            price = price.replace(digit_group_separator, "")
+        if digit_group_separator is not None and price is not None:
+            price = price.replace(digit_group_separator, '')
         amount_text = extract_price_text(price) if price is not None else None
         amount_num = (
             parse_number(amount_text, decimal_separator)
diff --git a/setup.py b/setup.py
index 47a8c08..cfc200f 100755
--- a/setup.py
+++ b/setup.py
@@ -19,14 +19,19 @@
     ],
     zip_safe=False,
     classifiers=[
-        "Development Status :: 4 - Beta",
-        "Intended Audience :: Developers",
-        "License :: OSI Approved :: BSD License",
-        "Natural Language :: English",
-        "Operating System :: OS Independent",
-        "Programming Language :: Python :: 3",
-        "Programming Language :: Python :: 3.6",
-        "Programming Language :: Python :: 3.7",
-        "Programming Language :: Python :: 3.8",
+        'Development Status :: 4 - Beta',
+        'Intended Audience :: Developers',
+        'License :: OSI Approved :: BSD License',
+        'Natural Language :: English',
+        'Operating System :: OS Independent',
+        'Programming Language :: Python :: 3',
+        'Programming Language :: Python :: 3.6',
+        'Programming Language :: Python :: 3.7',
+        'Programming Language :: Python :: 3.8',
+        'Programming Language :: Python :: 3.9',
+        'Programming Language :: Python :: 3.10',
+        'Programming Language :: Python :: 3.11',
+        'Programming Language :: Python :: 3.12',
+        'Programming Language :: Python :: 3.13',
     ],
 )
diff --git a/tox.ini b/tox.ini
index b695b05..f6e7389 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = py36,py37,py38,mypy
+envlist = py36,py37,py38,py39,py310,py311,py312,py313,mypy
 
 [testenv]
 deps =