diff --git a/tests/test_comments_rules.py b/tests/test_comments_rules.py
new file mode 100644
index 0000000..a0dd076
--- /dev/null
+++ b/tests/test_comments_rules.py
@@ -0,0 +1,241 @@
+# This file is to test comment format for .rules files as stated in (Issue 23)
+import unittest
+import io
+import sys
+import tempfile
+import os
+
+from universalmutator.mutator import parseRules
+
+# written tests, still not tested!
+
+class TestParseRulesComments(unittest.TestCase):
+
+    def _parse(self, rule_text):
+        """
+        Helper: write rules to temp file, run parseRules, capture stdout
+        """
+        fd, path = tempfile.mkstemp(suffix=".rules")
+        os.close(fd)
+
+        try:
+            with open(path, "w") as f:
+                f.write(rule_text)
+
+            # capture print output
+            buffer = io.StringIO()
+            old_stdout = sys.stdout
+            sys.stdout = buffer
+
+            try:
+                rules, ignoreRules, skipRules = parseRules([path])
+            finally:
+                sys.stdout = old_stdout
+
+            return rules, ignoreRules, skipRules, buffer.getvalue()
+
+        finally:
+            os.remove(path)
+
+    # ---------------------------------------------------
+    # TEST 1: indented comments should be ignored
+    # ---------------------------------------------------
+    def test_indented_comments_ignored(self):
+        rules, ignoreRules, skipRules, out = self._parse(
+            "   # comment line\n"
+            "\t# tab comment\n"
+            "\\+ ==> -\n"
+        )
+
+        self.assertEqual(len(rules), 1)
+        self.assertEqual(len(ignoreRules), 0)
+        self.assertEqual(len(skipRules), 0)
+
+    # ---------------------------------------------------
+    # TEST 2: blank lines should be ignored
+    # ---------------------------------------------------
+    def test_blank_lines_ignored(self):
+        rules, _, _, out = self._parse(
+            "\\+ ==> -\n"
+            "\n"
+            "   \n"
+            "\\* ==> /\n"
+            "\t\n"
+        )
+
+        self.assertEqual(len(rules), 2)
+
+    # ---------------------------------------------------
+    # TEST 3: rules starting with '#' must NOT be treated as comments
+    # ---------------------------------------------------
+    def test_hash_rules_still_parse(self):
+        rules, ignoreRules, skipRules, out = self._parse(
+            "#include ==> DO_NOT_MUTATE\n"
+            "# ==> SKIP_MUTATING_REST\n"
+        )
+
+        self.assertEqual(len(ignoreRules), 1)
+        self.assertEqual(len(skipRules), 1)
+
+    # ---------------------------------------------------
+    # TEST 4: only comments should result in no rules and no warnings
+    # ---------------------------------------------------
+
+    def test_only_comments(self):
+        rules, ignoreRules, skipRules, out = self._parse(
+            "# comment\n"
+            "   # indented comment\n"
+            " # spaced comment\n"
+            "#\t tab comment\n"
+        )
+
+        self.assertEqual(len(rules), 0)
+        self.assertEqual(len(ignoreRules), 0)
+        self.assertEqual(len(skipRules), 0)
+
+    # ---------------------------------------------------
+    # TEST 5: Invalid lines should still warn, but not be treated as rules
+    # ---------------------------------------------------
+    def test_invalid_lines(self):
+        rules, ignoreRules, skipRules, out = self._parse(
+            "   # comment line\n"
+            "\t# tab comment\n"
+            "\\+ ==> -\n"
+            "# ==> SKIP_MUTATING_REST\n"
+            "invalid line\n"
+        )
+
+        self.assertEqual(len(rules), 1)
+        self.assertEqual(len(ignoreRules), 0)
+        self.assertEqual(len(skipRules), 1)
+
+    # ---------------------------------------------------
+    # TEST 6: Mixed file test with comments, blank lines, valid rules, and invalid lines
+    # ---------------------------------------------------
+    def test_mixed_file(self):
+        rules, ignoreRules, skipRules, out = self._parse(
+            "# comment\n"
+            "\n"
+            "   # indented comment\n"
+            " # spaced comment\n"
+            "\\+ ==> -\n"
+            "invalid line\n"
+            "# ==> SKIP_MUTATING_REST\n"
+        )
+
+        self.assertEqual(len(rules), 1)
+        self.assertEqual(len(ignoreRules), 0)
+        self.assertEqual(len(skipRules), 1)
+
+    # ---------------------------------------------------
+    # TEST 7: Disabled rules should be ignored, but still treated as comments
+    # ---------------------------------------------------
+    def test_disabled_rules_ignored(self):
+        rules, ignoreRules, skipRules, out = self._parse(
+            "#DISABLED: \\+ ==> -\n"
+            "#DISABLED: #include ==> DO_NOT_MUTATE\n"
+            "#DISABLED: # ==> SKIP_MUTATING_REST\n"
+            "\\* ==> /\n"
+        )
+
+        self.assertEqual(len(rules), 1)
+        self.assertEqual(len(ignoreRules), 0)
+        self.assertEqual(len(skipRules), 0)
+
+    # ---------------------------------------------------
+    # TEST 8: Disabled rules with different spacing should still be ignored (MAYBE?) Might be  problems
+    # ---------------------------------------------------
+    def test_disabled_rules_varied_spacing(self):
+        rules, ignoreRules, skipRules, out = self._parse(
+            "\t\t\t#DISABLED: \\+ ==> -\n"
+            "  #DISABLED: #include ==> DO_NOT_MUTATE\n"
+            "\t#DISABLED: # ==> SKIP_MUTATING_REST\n"
+            "\\* ==> /\n"
+        )
+
+        self.assertEqual(len(rules), 1)
+        self.assertEqual(len(ignoreRules), 0)
+        self.assertEqual(len(skipRules), 0)
+
+    # ---------------------------------------------------
+    # TEST 9: Header Testing with comments, blank lines before and after header, and example rules comments
+    # ---------------------------------------------------
+    def test_header_with_comments_and_blank_lines(self):
+        rules, ignoreRules, skipRules, out = self._parse(
+            "# This is a header comment\n"
+            "# It should be ignored\n"
+            "\n"
+            "# Another header comment\n"
+            "\n"
+            "# Example rule comment\n"
+            "#DISABLED: <code expression> ==> <replacement>\n"
+            "# This is an example rule that should be ignored\n"
+            "#DISABLED: #include ==> DO_NOT_MUTATE\n"
+        )
+
+        self.assertEqual(len(rules), 0)
+        self.assertEqual(len(ignoreRules), 0)
+        self.assertEqual(len(skipRules), 0)
+
+    # ---------------------------------------------------
+    # TEST 10: Larger file test with multiple comments, blank lines, valid rules, invalid lines, and disabled rules
+    # ---------------------------------------------------
+    def test_larger_mixed_file(self):
+        rules, ignoreRules, skipRules, out = self._parse(
+            "# =====================================================\n"
+            "# HEADER COMMENT BLOCK\n"
+            "# This file tests real-world mixed .rules behavior\n"
+            "# =====================================================\n"
+            "\n"
+            "# Simple arithmetic rules\n"
+            "\\+ ==> -\n"
+            "\\- ==> +\n"
+            "\n"
+            "# multiplication and division\n"
+            "\\* ==> /\n"
+            "\\/ ==> *\n"
+            "\n"
+            "   # indented comment inside file\n"
+            "\t# tab-indented comment\n"
+            "\n"
+            "#Disabled rule section\n"
+            "#DISABLED: \\+ ==> *\n"
+            "#DISABLED: \\* ==> +\n"
+            "\n"
+            "# Special ignore rule\n"
+            "#include ==> DO_NOT_MUTATE\n"
+            "\n"
+            "# Special skip rule\n"
+            "# ==> SKIP_MUTATING_REST\n"
+            "\n"
+            "# Invalid lines (should trigger warnings)\n"
+            "this is not a rule\n"
+            "==> broken rule\n"
+            "\\+ == bad format\n"
+            "\n"
+            "# More valid rules\n"
+            "== ==> !=\n"
+            "!= ==> ==\n"
+            "< ==> >\n"
+            "> ==> <\n"
+            "\n"
+            "# More noise\n"
+            "random text here\n"
+            "another bad line\n"
+            "\n"
+            "# Final valid rule\n"
+            "\\% ==> +\n"
+        )
+
+        # Expected valid rules:
+        # +, -, *, /, ==, !=, <, >, %
+        self.assertEqual(len(rules), 9)
+
+        # Only one ignore rule (#include ==> DO_NOT_MUTATE)
+        self.assertEqual(len(ignoreRules), 1)
+
+        # Only one skip rule (# ==> SKIP_MUTATING_REST)
+        self.assertEqual(len(skipRules), 1)
+
+if __name__ == "__main__":
+    unittest.main()
\ No newline at end of file
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diff --git a/universalmutator/mutator.py b/universalmutator/mutator.py
index 1791d61..b4e65b1 100644
--- a/universalmutator/mutator.py
+++ b/universalmutator/mutator.py
@@ -1,11 +1,38 @@
 from __future__ import print_function
 import re
-import pkg_resources
+import sys
 import random
 from comby import Comby
 import os
 from json.decoder import JSONDecodeError
 
+# Python 3.9+ has importlib.resources with the modern files() API.
+# Older Pythons (< 3.9) fall back to pkg_resources from setuptools.
+if sys.version_info >= (3, 9):
+    import importlib.resources as _importlib_resources
+    _use_importlib = True
+else:
+    try:
+        import importlib.resources as _importlib_resources
+        _use_importlib = True
+    except ImportError:
+        import pkg_resources as _pkg_resources
+        _use_importlib = False
+
+
+def _open_package_resource(package, resource_path):
+    """Open a package data file, using importlib.resources on Python 3.9+
+    and falling back to pkg_resources on older versions."""
+    if _use_importlib:
+        parts = resource_path.replace("\\", "/").split("/")
+        subpackage = package + "." + ".".join(parts[:-1]) if len(parts) > 1 else package
+        filename = parts[-1]
+        ref = _importlib_resources.files(subpackage).joinpath(filename)
+        return ref.open("rb")
+    else:
+        return _pkg_resources.resource_stream(package, resource_path)
+
+
 def parseRules(ruleFiles, comby=False):
     rulesText = []
 
@@ -17,7 +44,7 @@ def parseRules(ruleFiles, comby=False):
                 rulePath = os.path.join('comby', ruleFile)
             else:
                 rulePath = os.path.join('static', ruleFile)
-            with pkg_resources.resource_stream('universalmutator', rulePath) as builtInRule:
+            with _open_package_resource('universalmutator', rulePath) as builtInRule:
                 for line in builtInRule:
                     line = line.decode()
                     rulesText.append((line, "builtin:" + ruleFile))
@@ -37,22 +64,40 @@ def parseRules(ruleFiles, comby=False):
 
     for (r, ruleSource) in rulesText:
         ruleLineNo += 1
-        if r == "\n":
+
+        # remove all leading and trailing white space
+        line = r.strip()
+
+        # check for blank lines
+        if line == "":
+            # ignore blank lines
             continue
-        if " ==> " not in r:
-            if " ==>" in r:
-                s = r.split(" ==>")
-            else:
-                if r[0] == "#":  # Don't warn about comments
-                    continue
-                print("*" * 60)
-                print("WARNING:")
-                print("RULE:", r, "FROM", ruleSource)
-                print("DOES NOT MATCH EXPECTED FORMAT, AND SO WAS IGNORED")
-                print("*" * 60)
-                continue  # Allow blank lines and comments, just ignore lines without a transformation
+
+        # handle comments
+        if line.startswith("#") and "==>" not in line:
+            # ignore comments '#'
+            continue
+
+        # check for disabled rules
+        if line.startswith("#DISABLED:"):
+            # ignore disabled rules
+            continue
+
+        # check and parse valid rules
+        if " ==> " in line:
+            s = line.split(" ==> ")
+        elif " ==>" in line:
+            s = line.split(" ==>")
         else:
-            s = r.split(" ==> ")
+            # otherwise it's a invalid line and warn user
+            print("*" * 60)
+            print("WARNING:")
+            print("RULE:", line, "FROM", ruleSource)
+            print("DOES NOT MATCH EXPECTED FORMAT, AND SO WAS IGNORED")
+            print("*" * 60)
+            continue
+        
+                                                            # End of possible fix
 
         if comby:
             lhs = s[0]