fixing th condition and adding one more unit test

otc_doc_convertor/convertor.py

@@ -224,7 +224,7 @@ class OTCDocConvertor:
 
         # Drop strong in table headers "/"
         for th in soup.body.find_all("th"):
-            if th.p.strong:
+            if th.p and th.p.strong:
                 th.p.strong.unwrap()
 
         if args and args.improve_table_headers:

otc_doc_convertor/tests/unit/test_convertor.py

@@ -219,3 +219,31 @@ class TestConvertor(TestCase):
             str(res.find('p')),
             expected.strip(),
         )
+
+    def test_streamline_html_escape_16(self):
+        test_data= """
+        <th align="left" class="cellrowborder" id="mcps1.3.2.3.2.5.1.2" valign="top" width="20%"><p><strong>Mandatory</strong></p></th>
+        """ # noqa
+        expected = """
+        <th align="left" class="cellrowborder" id="mcps1.3.2.3.2.5.1.2" valign="top" width="20%"><p>Mandatory</p></th>
+        """ # noqa
+        soup = bs4.BeautifulSoup(test_data, 'lxml')
+        res = self.convertor.streamline_html(soup, "dummy")
+        self.assertEqual(
+            str(res.find('th')),
+            expected.strip(),
+        )
+
+    def test_streamline_html_escape_17(self):
+        test_data= """
+        <th align="left" class="cellrowborder" id="mcps1.3.2.3.2.5.1.2" valign="top" width="20%">Mandatory</th>
+        """ # noqa
+        expected = """
+        <th align="left" class="cellrowborder" id="mcps1.3.2.3.2.5.1.2" valign="top" width="20%">Mandatory</th>
+        """ # noqa
+        soup = bs4.BeautifulSoup(test_data, 'lxml')
+        res = self.convertor.streamline_html(soup, "dummy")
+        self.assertEqual(
+            str(res.find('th')),
+            expected.strip(),
+        )