fix apt module import

tests/test_postgresql.py

@@ -20,6 +20,7 @@ except ImportError:
 sys.path.append(str(Path(__file__).parents[1].resolve()))
 
 import utils as u
+from utils.apt import Apt
 
 
 def is_ha(port: int) -> bool:
@@ -379,7 +380,7 @@ def check_local(db_conn: dict, errors: int = 0) -> int:
 def main():
     """Run all checks and exits with corresponding exit code."""
 
-    apt = u.apt.Apt()
+    apt = Apt()
     if "postgresql" not in apt.installed_packages:
         exit(2)