diff --git a/zx.py b/zx.py
index 64ccd2d..3eb3db5 100644
--- a/zx.py
+++ b/zx.py
@@ -133,7 +133,7 @@ def modify_attr(attr: ast.Attribute) -> None:
         if (
             isinstance(attr.value, ast.UnaryOp)
             and isinstance(attr.value.op, ast.Invert)
-            and isinstance(attr.value.operand, ast.Constant)
+            and isinstance(attr.value.operand, (ast.Constant, ast.Str, ast.JoinedStr))
         ):
             attr.value = ast.Call(
                 func=ast.Name(id='run_shell', ctx=ast.Load()),