diff --git a/unit-testing.html b/unit-testing.html
index c836dee..625252a 100755
--- a/unit-testing.html
+++ b/unit-testing.html
@@ -406,7 +406,7 @@ FAILED (failures=2)</samp></pre>
 <p class=d>[<a href=examples/roman3.py>download <code>roman3.py</code></a>]
 <pre><code class=pp>def to_roman(n):
     '''convert integer to Roman numeral'''
-<a>    if not (0 < n < 4000):                                              <span class=u>&#x2460;</span></a>
+<a>    if not (0 &lt; n &lt; 4000):                                              <span class=u>&#x2460;</span></a>
 <a>        raise OutOfRangeError('number out of range (must be 0..3999)')  <span class=u>&#x2461;</span></a>
 
     result = ''
@@ -494,7 +494,7 @@ FAILED (failures=1)</samp></pre>
 
 <pre><code class=pp>def to_roman(n):
     '''convert integer to Roman numeral'''
-    if not (0 < n < 4000):
+    if not (0 &lt; n &lt; 4000):
         raise OutOfRangeError('number out of range (must be 0..3999)')
 <a>    if not isinstance(n, int):                                          <span class=u>&#x2460;</span></a>
 <a>        raise NotIntegerError('non-integers can not be converted')      <span class=u>&#x2461;</span></a>