diff --git a/precli/core/argument.py b/precli/core/argument.py
index c11322bb..b57784dd 100644
--- a/precli/core/argument.py
+++ b/precli/core/argument.py
@@ -24,7 +24,7 @@ def __init__(
         self._value_str = utils.to_str(value) if self._is_str else None
 
     @staticmethod
-    def _get_func_ident(node: Node) -> Node | None:
+    def _get_func_ident(node: Node) -> Optional[Node]:
         if node is None:
             return None
         # TODO(ericwb): does this function fail with nested calls?
@@ -41,7 +41,7 @@ def node(self) -> Node:
         return self._node
 
     @property
-    def identifier_node(self) -> Node | None:
+    def identifier_node(self) -> Optional[Node]:
         """
         The node representing just the identifier of the argument.
 
@@ -82,6 +82,6 @@ def value(self):
         return self._value
 
     @property
-    def value_str(self) -> str | None:
+    def value_str(self) -> Optional[str]:
         """The value as a true string."""
         return self._value_str
diff --git a/precli/core/config.py b/precli/core/config.py
index bd8bfedb..81cc5545 100644
--- a/precli/core/config.py
+++ b/precli/core/config.py
@@ -19,7 +19,7 @@ def enabled(self) -> bool:
         return self._enabled
 
     @enabled.setter
-    def enabled(self, enabled):
+    def enabled(self, enabled: bool):
         """Set whether the rule is enabled"""
         self._enabled = enabled
 
diff --git a/precli/core/run.py b/precli/core/run.py
index bd310fb6..b00c4a85 100644
--- a/precli/core/run.py
+++ b/precli/core/run.py
@@ -79,8 +79,8 @@ def parse_file(
             Result(
                 f"{parser.rule_prefix()}000" if parser else "NO_RULE",
                 location=Location(
-                    start_line=e.lineno,
-                    end_line=e.lineno,
+                    start_line=e.lineno if e.lineno else 0,
+                    end_line=e.lineno if e.lineno else 0,
                 ),
                 artifact=artifact,
                 level=Level.ERROR,
diff --git a/precli/core/symtab.py b/precli/core/symtab.py
index 3031f60c..fd592a34 100644
--- a/precli/core/symtab.py
+++ b/precli/core/symtab.py
@@ -5,7 +5,7 @@
 
 
 class SymbolTable:
-    def __init__(self, name, parent=None):
+    def __init__(self, name: str, parent=None):
         self._name = name
         self._parent = parent
         self._symbols = {}
@@ -46,7 +46,7 @@ def __str__(self) -> str:
 
 
 class Symbol:
-    def __init__(self, name, type, value):
+    def __init__(self, name: str, type: str, value: str):
         self._name = name
         self._type = type
         self._value = value