diff --git a/tools_v2.py b/tools_v2.py
index d728890..42f660e 100644
--- a/tools_v2.py
+++ b/tools_v2.py
@@ -77,7 +77,7 @@ class DockerTools:
     def ps(all_containers: bool = False) -> str:
         """Lista containers Docker."""
         flags = "-a" if all_containers else ""
-        result = run_bash(f"docker ps {flags} --format 'table {{.Names}}\t{{.Status}}\t{{.Ports}}'")
+        result = run_bash("docker ps " + flags + " --format 'table {{.Names}}\t{{.Status}}\t{{.Ports}}'")
         return format_output(result)
     
     @staticmethod