diff --git a/PyTeX/format/formatting_config.py b/PyTeX/format/formatting_config.py
index 1d48619..e1bd3da 100644
--- a/PyTeX/format/formatting_config.py
+++ b/PyTeX/format/formatting_config.py
@@ -14,38 +14,46 @@ class GitVersionInfo(Config):
         self._pytex_version: Optional[RepoStatusInfo] = None
 
     def set_from_json(self, content: Optional[Dict]):
-        content = self._fill_keys(content)
+        filled_content = self._fill_keys(content)
         self._repo_version = RepoStatusInfo.from_json(
-            content[YAML_REPO]
+            filled_content[YAML_REPO]
         )
         self._pytex_version = RepoStatusInfo.from_json(
-            content[YAML_PYTEX]
+            filled_content[YAML_PYTEX]
         )
 
     def to_json(self) -> Dict:
         return {
-            YAML_PYTEX: self._pytex_version.to_json(),
-            YAML_REPO: self._repo_version.to_json()
+            YAML_PYTEX: self.pytex_version.to_json(),
+            YAML_REPO: self.repo_version.to_json()
         }
 
     @property
-    def pytex_version(self) -> Optional[RepoStatusInfo]:
+    def pytex_version(self) -> RepoStatusInfo:
         if self._pytex_version is None:
-            return None
+            return RepoStatusInfo()
         else:
             return self._pytex_version
 
     @property
-    def repo_version(self) -> Optional[RepoStatusInfo]:
+    def repo_version(self) -> RepoStatusInfo:
         if self._repo_version is None:
-            return None
+            return RepoStatusInfo()
         else:
             return self._repo_version
 
+    @property
+    def has_pytex_version(self) -> bool:
+        return self._pytex_version is None
+
+    @property
+    def has_repo_version(self) -> bool:
+        return self._repo_version is None
+
 
 class FormattingConfig(Config):
     def __init__(self):
-        self._naming_scheme: Optional[Union[NamingScheme, str]] = None
+        self._naming_scheme: Optional[NamingScheme] = None
         self._license: Optional[GenericText] = None
         self._description: Optional[str] = None
 
@@ -74,9 +82,9 @@ class FormattingConfig(Config):
         self._tex_flavour: Optional[TeXFlavour] = None
 
     def set_from_json(self, content: Optional[Dict]):
-        content = self._fill_keys(content)
+        filled_content = self._fill_keys(content)
 
-        info = content[YAML_INFO]
+        info = filled_content[YAML_INFO]
         self._author = info[YAML_AUTHOR]
         self._naming_scheme = info[YAML_NAMING_SCHEME]
         self._tex_flavour = info[YAML_TEX_FLAVOUR]
@@ -84,7 +92,7 @@ class FormattingConfig(Config):
         self._description = info[YAML_DESCRIPTION]
         self._version = info[YAML_VERSION]
 
-        header = content[YAML_HEADER]
+        header = filled_content[YAML_HEADER]
         extra = header[YAML_EXTRA]
         self._include_extra_header = extra[YAML_INCLUDE_EXTRA_HEADER]
         self._extra_header = GenericText(
@@ -113,7 +121,7 @@ class FormattingConfig(Config):
             license_[YAML_PATH] if license_[YAML_PATH] else license_[YAML_TEXT]
         )
 
-        docstrip = content[YAML_DOCSTRIP]
+        docstrip = filled_content[YAML_DOCSTRIP]
         self._include_drv = docstrip[YAML_INCLUDE_DRV]
         self._include_ins = docstrip[YAML_INCLUDE_INS]
         self._docstrip_guards = docstrip[YAML_DOCSTRIP_GUARDS]
diff --git a/PyTeX/format/generic_text.py b/PyTeX/format/generic_text.py
index 17065aa..dd6bbc1 100644
--- a/PyTeX/format/generic_text.py
+++ b/PyTeX/format/generic_text.py
@@ -12,7 +12,7 @@ class GenericText:
             self._path = None
             self._initialized = True
         elif isinstance(content, Path) or isinstance(content, str):
-            self._content: Optional[List[str]] = None
+            self._content = None
             self._path = Path(content)
             self._initialized = True
         else:
@@ -24,6 +24,8 @@ class GenericText:
     def text(self) -> List[str]:
         if self._initialized:
             if self._content is None:
+                if self._path is None:
+                    raise NotImplementedError  # Programming error
                 try:
                     with open(self._path, 'r') as file:
                         self._content = file.readlines()
diff --git a/PyTeX/format/macros.py b/PyTeX/format/macros.py
index 2c4354e..70c4c4e 100644
--- a/PyTeX/format/macros.py
+++ b/PyTeX/format/macros.py
@@ -30,7 +30,7 @@ class Argument(MacroReplacementAtomIF, Enum):
     six = 6
 
 
-class MacroReplacement(str):
+class MacroReplacement:
     def __init__(
             self,
             replacement: str,
diff --git a/PyTeX/format/repo_status_info.py b/PyTeX/format/repo_status_info.py
index fb05412..241e40e 100644
--- a/PyTeX/format/repo_status_info.py
+++ b/PyTeX/format/repo_status_info.py
@@ -13,11 +13,11 @@ class RepoStatusInfo(Config):
         self._version: Optional[str] = None
 
     def set_from_json(self, content: Optional[Dict]):
-        content = self._fill_keys(content)
-        self._branch = content[JSON_BRANCH]
-        self._dirty = content[JSON_DIRTY]
-        self._commit_hash = content[JSON_COMMIT_HASH]
-        self._version = content[JSON_VERSION]
+        filled_content: Dict = self._fill_keys(content)
+        self._branch = filled_content[JSON_BRANCH]
+        self._dirty = filled_content[JSON_DIRTY]
+        self._commit_hash = filled_content[JSON_COMMIT_HASH]
+        self._version = filled_content[JSON_VERSION]
 
     def to_json(self) -> Dict:
         return {