diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index d366216691614ba0ba50f30d9df907f7477d85a7..d6680778927ca83d0cd4d0970b66a927fbdea777 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -43,3 +43,39 @@ test_python310:
 test_python311:
   extends: .test_python
   image: python:3.11
+
+
+.build_python:
+  only:
+    - master
+  stage: build
+  script:
+    - pip install --break-system-packages --upgrade Cython setuptools pip
+    - pip install --break-system-packages -r requirements.txt
+    - python setup.py bdist_wheel
+    - cp dist/*.whl .
+  artifacts:
+    paths:
+      - "*.whl"
+
+build_python38:
+  extends: .build_python
+  image: python:3.8
+
+build_python39:
+  extends: .build_python
+  image: python:3.9
+
+
+build_python310:
+  extends: .build_python
+  image: python:3.10
+
+
+build_python38:
+  extends: .build_python
+  image: python:3.11
+
+build_python311_armv7l:
+  extends: .build_python
+  image: zoo.smok.co/build/build:armv7l-python311
diff --git a/tempsdb/series.pyx b/tempsdb/series.pyx
index 47ba142a09c9b99edcf8f18120fd2d9e2d71e119..f9701a016130522feacbc1a8ae99da17d41e4337 100644
--- a/tempsdb/series.pyx
+++ b/tempsdb/series.pyx
@@ -453,7 +453,7 @@ cdef class TimeSeries:
         :raises ValueError: Timestamp not larger than previous timestamp or invalid block size
         :raises InvalidState: the resource is closed
         """
-        cdef int data_len = len(data)
+        cdef unsigned int data_len = len(data)
         if data_len > self.block_size:
             raise ValueError('Data too long')
         data = data + b'\x00'*(self.block_size - data_len)