diff --git a/src/epub_postprocessor.py b/src/epub_postprocessor.py
index e559f6e..d243300 100644
--- a/src/epub_postprocessor.py
+++ b/src/epub_postprocessor.py
@@ -313,7 +313,7 @@ class EpubPostprocessor:
                     if anchor_tag.attrs['id'] not in self.internal_anchors:
                         new_anchor_span = self._create_new_anchor_span(soup, new_id)
                         anchor_tag.insert_before(new_anchor_span)
-                        self.internal_anchors.add(anchor_tag.attrs['id'])
+                        self.internal_anchors.add(new_id)
                         del anchor_tag.attrs['id']
                     del internal_link_tag.attrs['href']
 
diff --git a/src/html_epub_preprocessor.py b/src/html_epub_preprocessor.py
index d061df7..1e01690 100644
--- a/src/html_epub_preprocessor.py
+++ b/src/html_epub_preprocessor.py
@@ -377,7 +377,7 @@ def get_tags_between_chapter_marks(first_id, href, html_soup):
     return tags
 
 
-def wrap_span_with_table(main_tag, old_tag):
+def wrap_preformatted_span_with_table(main_tag, old_tag):
     table = main_tag.new_tag("table")
     table.attrs['border'] = '1px solid #ccc;'
     table.attrs['style'] = 'width:100%;'
@@ -393,7 +393,7 @@ def wrap_span_with_table(main_tag, old_tag):
     return table
 
 
-def wrap_block_with_table(main_tag, old_tag, color=None):
+def wrap_block_tag_with_table(main_tag, old_tag, bg_color=None):
     table = main_tag.new_tag("table")
     table.attrs['border'] = '1px solid'
     table.attrs['align'] = 'center'
@@ -402,8 +402,8 @@ def wrap_block_with_table(main_tag, old_tag, color=None):
     tr = main_tag.new_tag("tr")
     td = main_tag.new_tag("td")
     # td.attrs['border-radius'] = '8px'
-    if color:
-        td.attrs['bgcolor'] = color
+    if bg_color:
+        td.attrs['bgcolor'] = bg_color
     old_tag.wrap(td)
     td.wrap(tr)
     tr.wrap(tbody)
@@ -426,7 +426,7 @@ def preprocess_block_tags(chapter_tag):
 
             color = '#DDDDDD' if block.attrs.get('class') == 'feature1' else None
             color = '#EEEEEE' if block.attrs.get('class') == 'feature2' else color
-            wrap_block_with_table(chapter_tag, block, color)
+            wrap_block_tag_with_table(chapter_tag, block, color)
             block.insert_after(BeautifulSoup(features='lxml').new_tag("br"))
             block.unwrap()
 
@@ -464,7 +464,7 @@ def preprocess_pre_tags(chapter_tag):
                                  "font-size: 14px; white-space: nowrap;"
         pre.insert_before(new_tag)
         pre.extract()
-        table = wrap_span_with_table(chapter_tag, new_tag)
+        table = wrap_preformatted_span_with_table(chapter_tag, new_tag)
         p_for_br = chapter_tag.new_tag("p")
         p_for_br.string = "\xa0"
         table.insert_after(p_for_br)