diff --git a/source/pip_runner.py b/source/pip_runner.py
index f23a058..a01bbfc 100644
--- a/source/pip_runner.py
+++ b/source/pip_runner.py
@@ -29,7 +29,7 @@ class PipRunner(unohelper.Base, XJob):
         if self._is_flatpak:
             site_packages = self.get_flatpak_site_packages_dir()
             ss = str(site_packages)
-            if site_packages.exists and  ss not in sys.path:
+            if site_packages.exists() and  ss not in sys.path:
                 sys.path.append(ss)
     
     def execute(self, *args: Tuple[NamedValue, ...]) -> None: