diff --git a/pulses/pulses.py b/pulses/pulses.py
index 7d08ba4..f056200 100644
--- a/pulses/pulses.py
+++ b/pulses/pulses.py
@@ -77,7 +77,7 @@ class ledPulse(threading.Thread):
             pass
 
         if self.supported:
-            import RPi.GPIO as GPIO
+            import RPi.GPIO as GPIO  # type: ignore
             GPIO.setwarnings(False)          # disable warnings
             GPIO.setmode(GPIO.BCM)           # set pin numbering system
             GPIO.setup(self.gpio, GPIO.OUT)  # set GPIO for output
diff --git a/pyproject.toml b/pyproject.toml
index 2b70da7..86b4f58 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,12 +1,12 @@
 [tool.poetry]
 name = "pulses"
-version = "1.0.0"
+version = "1.0.1"
 description = "Pulse LEDs on RPi"
 authors = ["Andrea Mistrali <andrea@mistrali.pw>"]
 readme = "README.md"
 
 [tool.poetry.dependencies]
-python = "^3.11"
+python = ">=3.9,<4.0"
 docopt = "^0.6.2"
 
 [tool.poetry.scripts]
diff --git a/requirements-dev.txt b/requirements-dev.txt
index 3ddafa3..3e659bf 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -1,2 +1,2 @@
-build
+poetry
 ipython