diff --git a/amarna/command_line.py b/amarna/command_line.py
index 53ede46..8bf04a7 100644
--- a/amarna/command_line.py
+++ b/amarna/command_line.py
@@ -4,6 +4,7 @@
 from amarna.Result import Result, ResultMultiplePositions, output_result
 from amarna.Result import SARIF_MODE, SUMMARY_MODE
 from typing import List, Union
+import sys
 
 example_usage = """---------------\nUsage examples\n---------------
 Analyze a Cairo project in the current directory and export results to a file:
@@ -42,7 +43,7 @@ def get_rule_names(rules: str, excluded: str) -> List[str]:
     for rule in rules + excluded:
         if rule not in ALL_RULES:
             print("Unknown rule: " + repr(rule))
-            exit(-1)
+            sys.exit(-1)
 
     if rules:
         base_rules = rules
@@ -84,7 +85,7 @@ def filter_results_from_disable(
     return new_results
 
 
-def main() -> None:
+def main() -> int:
     parser = argparse.ArgumentParser(
         description="Amarna is a static-analyzer for the Cairo programming language.",
         epilog=example_usage,
@@ -170,6 +171,8 @@ def main() -> None:
     if args.output or args.print:
         output_result(results, args.output, args.print, mode)
 
+    return 0
+
 
 if __name__ == "__main__":
     main()
diff --git a/amarna/rules/gatherer_rules/FunctionsEmittingEventsGatherer.py b/amarna/rules/gatherer_rules/FunctionsEmittingEventsGatherer.py
index 41ed88c..9dc8244 100644
--- a/amarna/rules/gatherer_rules/FunctionsEmittingEventsGatherer.py
+++ b/amarna/rules/gatherer_rules/FunctionsEmittingEventsGatherer.py
@@ -34,11 +34,15 @@ def get_gathered_data(self) -> List[FunctionEmittingEvent]:
         return self.functions_emitting_events
 
     def code_element_function(self, tree: Tree) -> None:
+        function_name = None
+
         for child in tree.children:
             if child.data == "identifier_def":
                 function_name = str(child.children[0])
                 break
 
+        assert function_name != None
+
         events_emitted_list: List[EventEmitType] = []
 
         for call in tree.find_data("function_call"):
diff --git a/amarna/rules/local_rules/UnusedImportRule.py b/amarna/rules/local_rules/UnusedImportRule.py
index 3c4f6d6..b282a8e 100644
--- a/amarna/rules/local_rules/UnusedImportRule.py
+++ b/amarna/rules/local_rules/UnusedImportRule.py
@@ -1,4 +1,4 @@
-from typing import Set
+from typing import List, Set
 from lark import Tree, Token
 from amarna.Result import PositionType, create_result
 
@@ -56,21 +56,20 @@ def cairo_file(self, tree: Tree) -> None:
             return
 
         # gather all hint code and check if the imports are there
-        all_hints = ""
+        all_hints: List[str] = []
         for hint in self.original_tree.find_data("code_element_hint"):
-            all_hints += hint.children[0]
+            all_hints.append(hint.children[0])
+
+        hints_str = "\n".join(all_hints)
 
         # remove imports used in hints
         used_in_hints = set()
         for unused in unused_imports:
-            if unused.value in all_hints:
+            if unused.value in hints_str:
                 used_in_hints.add(unused)
 
         unused_imports = unused_imports - used_in_hints
 
-        # if unused_imports:
-        #     print(f"In file {self.fname}:")
-
         # report unused imports
         for arg in sorted(unused_imports):
             # print(f"\t{arg.value} imported at line {arg.line}")
diff --git a/amarna/rules/post_process_rules/UnenforcedViewRule.py b/amarna/rules/post_process_rules/UnenforcedViewRule.py
index 8553105..3f9bf0b 100644
--- a/amarna/rules/post_process_rules/UnenforcedViewRule.py
+++ b/amarna/rules/post_process_rules/UnenforcedViewRule.py
@@ -1,6 +1,5 @@
 from typing import Dict, List
 from amarna.Result import ResultMultiplePositions, result_multiple_positions
-from amarna.rules.GenericRule import GenericRule
 
 from amarna.rules.gatherer_rules.DeclaredFunctionsGatherer import (
     DeclaredFunctionsGatherer,
@@ -12,7 +11,7 @@
 )
 
 
-class UnenforcedViewRule(GenericRule):
+class UnenforcedViewRule:
     """
     Find state modifications in functions with @view decorator.
     """