diff --git a/setup.cfg b/setup.cfg
index 6626e5f..7466cf2 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -7,7 +7,7 @@ classifiers =
     Operating System :: OS Independent
 
 [options]
-python_requires = >=3.10
+python_requires = >=3.9
 install_requires = 
     numpy
     openpyxl
diff --git a/tox.ini b/tox.ini
index 05f93e7..a8bec26 100644
--- a/tox.ini
+++ b/tox.ini
@@ -7,7 +7,7 @@ python =
     3.11: python3.11
 
 [testenv]
-deps = -r requirements_dev.txt
+deps = -rrequirements_dev.txt
 commands = 
     # black
     black src/