diff --git a/pyproject.toml b/pyproject.toml
index 8ec331d..b888d65 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -17,7 +17,7 @@ namespaces = true
 # ----------------------------------------- Project Metadata -------------------------------------
 #
 [project]
-version = "0.0.0.dev48"
+version = "0.0.0.dev49"
 name = "PySerials"
 dependencies = [
     "jsonschema >= 4.21.0, < 5",
@@ -26,8 +26,8 @@ dependencies = [
     "ruamel.yaml >= 0.17.32, < 0.18", # https://yaml.readthedocs.io/en/stable/
     "ruamel.yaml.string >= 0.1.1, < 1",
     "tomlkit >= 0.11.8, < 0.12", # https://tomlkit.readthedocs.io/en/stable/,
-    "MDit == 0.0.0.dev45",
-    "ExceptionMan == 0.0.0.dev45",
+    "MDit == 0.0.0.dev46",
+    "ExceptionMan == 0.0.0.dev46",
     "ProtocolMan == 0.0.0.dev2",
 ]
 requires-python = ">=3.10"
diff --git a/requirements.txt b/requirements.txt
index 405b89f..758e3e4 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -4,6 +4,6 @@ jsonpath-ng >= 1.6.1, < 2
 ruamel.yaml >= 0.17.32, < 0.18
 ruamel.yaml.string >= 0.1.1, < 1
 tomlkit >= 0.11.8, < 0.12
-MDit == 0.0.0.dev45
-ExceptionMan == 0.0.0.dev45
+MDit == 0.0.0.dev46
+ExceptionMan == 0.0.0.dev46
 ProtocolMan == 0.0.0.dev2
\ No newline at end of file
diff --git a/src/pyserials/exception/update.py b/src/pyserials/exception/update.py
index ef7a0ed..a8b8b03 100644
--- a/src/pyserials/exception/update.py
+++ b/src/pyserials/exception/update.py
@@ -128,7 +128,8 @@ def __init__(
         self.template_start = template_start
         self.template_end = template_end
         parts = description_template.split("{path_invalid}")
-        parts.insert(1, _mdit.element.code_span(self.path_invalid))
+        if len(parts) > 1:
+            parts.insert(1, _mdit.element.code_span(self.path_invalid))
         super().__init__(
             path=path.replace("'", ""),
             data=data,
diff --git a/src/pyserials/update.py b/src/pyserials/update.py
index a0a59c0..678685a 100644
--- a/src/pyserials/update.py
+++ b/src/pyserials/update.py
@@ -152,6 +152,7 @@ def __init__(
 
         self._pattern_value: dict[int, _RegexPattern] = {}
         self._data = None
+        self._visited_paths = set()
         return
 
     def fill(
@@ -161,6 +162,7 @@ def fill(
         current_path: str = "",
     ):
         self._data = data
+        self._visited_paths = set()
         path = (f"$.{current_path}" if self._add_prefix else current_path) if current_path else "$"
         return self._recursive_subst(
             templ=template or data,
@@ -198,13 +200,15 @@ def getter_function(path: str, default: Any = None, search: bool = False):
             local_context = {}
             try:
                 exec(code_str_full, global_context, local_context)
-                return local_context["__inline_code__"]()
+                output = local_context["__inline_code__"]()
             except Exception as e:
                 raise_error(
                     description_template=f"Code at {{path_invalid}} raised an exception: {e}\n{code_str_full}",
                     path_invalid=current_path,
                     exception=e,
                 )
+            self._visited_paths.add(self._normalize_path(current_path))
+            return output
 
         def get_address_value(match: _re.Match | str, return_all_matches: bool = False, from_code: bool = False):
             raw_path = match if isinstance(match, str) else str(match.group(1))
@@ -238,6 +242,7 @@ def get_address_value(match: _re.Match | str, return_all_matches: bool = False,
                     root_path_expr = root_path_expr.left
                 path_expr = self._concat_json_paths(root_path_expr, path_expr)
             value, matched = get_value(path_expr, return_all_matches, from_code)
+            self._visited_paths.add(self._normalize_path(current_path))
             if from_code:
                 return value, matched
             if matched:
@@ -337,6 +342,8 @@ def raise_error(path_invalid: str, description_template: str, exception: Excepti
             ) from exception
 
         self._check_endless_loop(templ, current_chain)
+        # if self._normalize_path(current_path) in self._visited_paths:
+        #     return templ
 
         if isinstance(templ, str):
             # Handle value blocks
@@ -393,9 +400,16 @@ def raise_error(path_invalid: str, description_template: str, exception: Excepti
                     current_chain=current_chain + [new_path],
                 )
                 if isinstance(elem, str) and self._pattern_unpack.fullmatch(elem):
-                    out.extend(elem_filled)
+                    try:
+                        out.extend(elem_filled)
+                    except TypeError as e:
+                        raise_error(
+                            path_invalid=current_path,
+                            description_template=str(e)
+                        )
                 else:
                     out.append(elem_filled)
+            self._visited_paths.add(self._normalize_path(current_path))
             return out
 
         if isinstance(templ, dict):
@@ -422,6 +436,7 @@ def raise_error(path_invalid: str, description_template: str, exception: Excepti
                     level=0,
                     current_chain=current_chain + [new_path],
                 )
+            self._visited_paths.add(self._normalize_path(current_path))
             return new_dict
         return templ
 
@@ -480,6 +495,10 @@ def _recursive_extract(expr):
         _recursive_extract(jsonpath)
         return fields
 
+    @staticmethod
+    def _normalize_path(path: str) -> str:
+        return path.replace("'", "")
+
     def _concat_json_paths(self, path1, path2):
         if not isinstance(path2, _jsonpath.Child):
             return _jsonpath.Child(path1, path2)
diff --git a/src/pyserials/write.py b/src/pyserials/write.py
index 2008bed..dd43ef1 100644
--- a/src/pyserials/write.py
+++ b/src/pyserials/write.py
@@ -2,6 +2,7 @@
 from pathlib import Path as _Path
 import json as _json
 import ruamel.yaml as _yaml
+from ruamel.yaml import scalarstring as _yaml_scalar_string
 import tomlkit as _tomlkit
 
 
@@ -22,8 +23,16 @@ def to_string(
 def to_yaml_string(
     data: dict | list | str | int | float | bool | _yaml.CommentedMap | _yaml.CommentedSeq,
     end_of_file_newline: bool = True,
+    indent_mapping: int = 2,
+    indent_sequence: int = 4,
+    indent_sequence_offset: int = 2,
+    multiline_string_to_block: bool = True,
 ) -> str:
-    yaml_syntax = _yaml.YAML(typ=["rt", "string"]).dumps(data, add_final_eol=False).removesuffix("\n...")
+    yaml = _yaml.YAML(typ=["rt", "string"])
+    yaml.indent(mapping=indent_mapping, sequence=indent_sequence, offset=indent_sequence_offset)
+    if multiline_string_to_block:
+        _yaml_scalar_string.walk_tree(data)
+    yaml_syntax = yaml.dumps(data, add_final_eol=False).removesuffix("\n...")
     return f"{yaml_syntax}\n" if end_of_file_newline else yaml_syntax
 
 
@@ -46,9 +55,17 @@ def to_yaml_file(
     data: dict | list | str | int | float | bool | _yaml.CommentedMap | _yaml.CommentedSeq,
     path: str | _Path,
     make_dirs: bool = True,
+    indent_mapping: int = 2,
+    indent_sequence: int = 4,
+    indent_sequence_offset: int = 2,
+    multiline_string_to_block: bool = True,
 ):
     path = _Path(path).resolve()
     if make_dirs:
         path.parent.mkdir(parents=True, exist_ok=True)
-    _yaml.YAML().dump(data, path)
+    yaml = _yaml.YAML()
+    yaml.indent(mapping=indent_mapping, sequence=indent_sequence, offset=indent_sequence_offset)
+    if multiline_string_to_block:
+        _yaml_scalar_string.walk_tree(data)
+    yaml.dump(data, path)
     return