diff --git a/ppp_tree.py b/ppp_tree.py
index 498476d..e15792f 100644
--- a/ppp_tree.py
+++ b/ppp_tree.py
@@ -2108,7 +2108,7 @@ class TreeProcessor(lark.visitors.Interpreter):
                 options = wildcard.unprocessed_choices[0]
                 container = options.get("container", None)
                 container_kind = "specified"
-                if container is None or not isinstance(container, str):
+                if container is None:
                     container_kind = "assembled"
                     has_separator = "separator" in options
                     has_prefix = "prefix" in options
@@ -2130,7 +2130,7 @@ class TreeProcessor(lark.visitors.Interpreter):
                     options.pop("prefix", None)
                     options.pop("suffix", None)
                     options.pop("container", None)
-                if container is not None:
+                if container is not None and isinstance(container, str):
                     try:
                         options["container"] = parse_prompt(
                             self.state, "choicevalue", container, self.state.parsers["choicevalue"], True
diff --git a/pyproject.toml b/pyproject.toml
index d163510..38a028b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,7 +1,7 @@
 [project]
 name = "sd-webui-prompt-postprocessor"
 description = "Stable Diffusion WebUI & ComfyUI extension to post-process the prompt, including sending content from the prompt to the negative prompt and wildcards."
-version = "3.1.0"
+version = "3.1.1"
 license = { file = "LICENSE.txt" }
 dependencies = ["lark", "numpy", "pyyaml", "pydantic"]