diff --git a/bin/python/isc/policy.py.in b/bin/python/isc/policy.py.in
index d3eb491db0..380af4da5a 100644
--- a/bin/python/isc/policy.py.in
+++ b/bin/python/isc/policy.py.in
@@ -61,17 +61,17 @@ class PolicyLex:
         t.lexer.lineno += t.value.count('\n')
 
     def t_DATESUFFIX(self, t):
-        r'(?i)(?<=[0-9 \t])(y(?:ears|ear|ea|e)?|mo(?:nths|nth|nt|n)?|w(?:eeks|eek|ee|e)?|d(?:ays|ay|a)?|h(?:ours|our|ou|o)?|mi(?:nutes|nute|nut|nu|n)?|s(?:econds|econd|econ|eco|ec|e)?)\b'
-        t.value = re.match(r'(?i)(y|mo|w|d|h|mi|s)([a-z]*)', t.value).group(1).lower()
+        r'(?<=[0-9 \t])(y(?:ears|ear|ea|e)?|mo(?:nths|nth|nt|n)?|w(?:eeks|eek|ee|e)?|d(?:ays|ay|a)?|h(?:ours|our|ou|o)?|mi(?:nutes|nute|nut|nu|n)?|s(?:econds|econd|econ|eco|ec|e)?)\b'
+        t.value = re.match(r'(y|mo|w|d|h|mi|s)([a-z]*)', t.value, re.IGNORECASE).group(1).lower()
         return t
 
     def t_KEYTYPE(self, t):
-        r'(?i)\b(KSK|ZSK)\b'
+        r'\b(KSK|ZSK)\b'
         t.value = t.value.upper()
         return t
 
     def t_ALGNAME(self, t):
-        r'(?i)\b(DH|ECC|RSASHA1|NSEC3RSASHA1|RSASHA256|RSASHA512|ECDSAP256SHA256|ECDSAP384SHA384|ED25519|ED448)\b'
+        r'\b(DH|ECC|RSASHA1|NSEC3RSASHA1|RSASHA256|RSASHA512|ECDSAP256SHA256|ECDSAP384SHA384|ED25519|ED448)\b'
         t.value = t.value.upper()
         return t
 
@@ -102,7 +102,7 @@ class PolicyLex:
             trans = maketrans('_', '-')
         for r in self.reserved:
             self.reserved_map[r.lower().translate(trans)] = r
-        self.lexer = lex.lex(object=self, **kwargs)
+        self.lexer = lex.lex(object=self, reflags=re.VERBOSE|re.IGNORECASE, **kwargs)
 
     def test(self, text):
         self.lexer.input(text)