diff --git a/googlemaps/maps.py b/googlemaps/maps.py
index eedcc42..763e012 100644
--- a/googlemaps/maps.py
+++ b/googlemaps/maps.py
@@ -75,8 +75,8 @@ class StaticMapMarker(StaticMapParam):
             self.params.append("color:%s" % color)
 
         if label:
-            if len(label) != 1 or not label.isupper() or not label.isalnum():
-                raise ValueError("Invalid label")
+            if len(label) != 1 or (label.isalpha() and not label.isupper()) or not label.isalnum():
+                raise ValueError("Marker label must be alphanumeric and uppercase.")
             self.params.append("label:%s" % label)
 
         self.params.append(convert.location_list(locations))

Static Maps: Numeric label raises a ValueError
A numeric (string) label should be supported (ex: '1') when creating a StaticMapMarker. However, an error is raised because of the line "if len(label) != 1 or not label.isupper() or not label.isalnum()" at line 78 (file maps.py).

The test label.isupper() returns false for '1', but it's a valid label.
diff --git a/tests/test_maps.py b/tests/test_maps.py
index db83ee0..8db6298 100644
--- a/tests/test_maps.py
+++ b/tests/test_maps.py
@@ -49,6 +49,8 @@ class MapsTest(TestCase):
         with self.assertRaises(ValueError):
             StaticMapMarker(locations=["Sydney"], label="XS")
 
+        self.assertEqual("label:1|Sydney", str(StaticMapMarker(locations=["Sydney"], label="1")))
+
     @responses.activate
     def test_static_map_path(self):
         path = StaticMapPath(

pip install -e .
parse_log_pytest
requirements.txt
pytest pytest-cov responses
apt-get update apt-get install -y gcc
3.9
requirements.txt
pytest --no-header -rA --tb=line --color=no -p no:cacheprovider -W ignore::DeprecationWarning
certifi==2025.1.31
charset-normalizer==3.4.1
coverage==7.8.0
exceptiongroup==1.2.2
-e git+https://github.com/googlemaps/google-maps-services-python.git@adf9cdeeb8eae5e1c07716b2138be2174e5972dd#egg=googlemaps
idna==3.10
iniconfig==2.1.0
packaging==24.2
pluggy==1.5.0
pytest==8.3.5
pytest-cov==6.0.0
PyYAML==6.0.2
requests==2.32.3
responses==0.25.7
tomli==2.2.1
urllib3==2.3.0

name: google-maps-services-python
channels:
  - defaults
  - https://repo.anaconda.com/pkgs/main
  - https://repo.anaconda.com/pkgs/r
  - conda-forge
dependencies:
  - _libgcc_mutex=0.1=main
  - _openmp_mutex=5.1=1_gnu
  - ca-certificates=2025.2.25=h06a4308_0
  - ld_impl_linux-64=2.40=h12ee557_0
  - libffi=3.4.4=h6a678d5_1
  - libgcc-ng=11.2.0=h1234567_1
  - libgomp=11.2.0=h1234567_1
  - libstdcxx-ng=11.2.0=h1234567_1
  - ncurses=6.4=h6a678d5_0
  - openssl=3.0.16=h5eee18b_0
  - pip=25.0=py39h06a4308_0
  - python=3.9.21=he870216_1
  - readline=8.2=h5eee18b_0
  - setuptools=75.8.0=py39h06a4308_0
  - sqlite=3.45.3=h5eee18b_0
  - tk=8.6.14=h39e8969_0
  - tzdata=2025a=h04d1e81_0
  - wheel=0.45.1=py39h06a4308_0
  - xz=5.6.4=h5eee18b_1
  - zlib=1.2.13=h5eee18b_1
  - pip:
      - certifi==2025.1.31
      - charset-normalizer==3.4.1
      - coverage==7.8.0
      - exceptiongroup==1.2.2
      - idna==3.10
      - iniconfig==2.1.0
      - packaging==24.2
      - pluggy==1.5.0
      - pytest==8.3.5
      - pytest-cov==6.0.0
      - pyyaml==6.0.2
      - requests==2.32.3
      - responses==0.25.7
      - tomli==2.2.1
      - urllib3==2.3.0
prefix: /opt/conda/envs/google-maps-services-python

tests/test_maps.py::MapsTest::test_static_map_marker
tests/test_maps.py::MapsTest::test_download tests/test_maps.py::MapsTest::test_static_map_path
googlemaps/maps.py
googlemaps/maps.py