Update documentation

Author: AllenDowney

_sources/chap13.ipynb

@@ -2128,8 +2128,12 @@
    "source": [
     "def replace_all(old, new, source_path, dest_path):\n",
     "    # read the contents of the source file\n",
+    "    reader = open(source_path)\n",
+    "\n",
     "    # replace the old string with the new\n",
-    "    # write the result into the destination file"
+    "    \n",
+    "    # write the result into the destination file\n",
+    "    "
    ]
   },
   {

chap13.html

@@ -1351,8 +1351,12 @@ <h3><span class="section-number">13.10.2. </span>Exercise<a class="headerlink" h
 <div class="cell_input docutils container">
 <div class="highlight-ipython3 notranslate"><div class="highlight"><pre><span></span><span class="k">def</span> <span class="nf">replace_all</span><span class="p">(</span><span class="n">old</span><span class="p">,</span> <span class="n">new</span><span class="p">,</span> <span class="n">source_path</span><span class="p">,</span> <span class="n">dest_path</span><span class="p">):</span>
     <span class="c1"># read the contents of the source file</span>
+    <span class="n">reader</span> <span class="o">=</span> <span class="nb">open</span><span class="p">(</span><span class="n">source_path</span><span class="p">)</span>
+
     <span class="c1"># replace the old string with the new</span>
+    
     <span class="c1"># write the result into the destination file</span>
+    
 </pre></div>
 </div>
 </div>