diff --git a/script-resources/common_script_utils.py b/script-resources/common_script_utils.py
index c85e21a..71bb093 100644
--- a/script-resources/common_script_utils.py
+++ b/script-resources/common_script_utils.py
@@ -13,11 +13,7 @@ def platform_not_supported_error() -> NoReturn:
   raise Exception("platform '{}' is not supported!".format(sys.platform))
 
 
-def run_chooser(
-  choices: Iterable[str],
-  prompt: Optional[str] = None,
-  async_read: bool = False,
-) -> int:
+def run_chooser(choices: Iterable[str], prompt: Optional[str] = None, async_read: bool = False) -> int:
   supports_result_index = True
   if os.isatty(sys.stderr.fileno()):
     process_args = [
@@ -45,8 +41,7 @@ def run_chooser(
 
   with chooser_process.stdin as pipe:
     for index, choice in enumerate(choices):
-
-      if "\n" in choice:
+      if "\n" not in choice:
         raise Exception("choices can only span a single line")
       if not supports_result_index:
         pipe.write(str(index).encode())