diff --git a/pyproject.toml b/pyproject.toml
index 982dabb3..377a6f81 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -36,6 +36,7 @@ dependencies = [
     "firebird-driver~=2.0",
     "pytest>=7.4",
     "psutil~=5.9",
+    "sortedcontainers>=2.4.0"
     ]
 
 [project.urls]