Update documentation

Author: AllenDowney

_sources/chap13.ipynb

@@ -2114,11 +2114,7 @@
   {
    "cell_type": "markdown",
    "id": "85844afb",
-   "metadata": {
-    "tags": [
-     "remove-cell"
-    ]
-   },
+   "metadata": {},
    "source": [
     "Here's an outline of the function to get you started."
    ]
@@ -2129,7 +2125,12 @@
    "id": "1e598e70",
    "metadata": {},
    "outputs": [],
-   "source": []
+   "source": [
+    "def replace_all(old, new, source_path, dest_path):\n",
+    "    # read the contents of the source file\n",
+    "    # replace the old string with the new\n",
+    "    # write the result into the destination file"
+   ]
   },
   {
    "cell_type": "code",

_sources/chap14.ipynb

@@ -447,7 +447,7 @@
    "metadata": {},
    "source": [
     "It might be surprising that the parameters have the same names as the attributes, but that's a common way to write a function like this.\n",
-    "Here's how we use `make_time` to create a `Time` object.`"
+    "Here's how we use `make_time` to create a `Time` object."
    ]
   },
   {
@@ -1225,7 +1225,7 @@
    "metadata": {},
    "source": [
     "The result is the number of seconds since the beginning of the day.\n",
-    "For example, `01:01:01` is `1` hour, `1` minute and `1` second from the beginning of the day, with is the sum of `3600` seconds, `60` seconds, and `1` second."
+    "For example, `01:01:01` is `1` hour, `1` minute and `1` second from the beginning of the day, which is the sum of `3600` seconds, `60` seconds, and `1` second."
    ]
   },
   {
@@ -1655,14 +1655,6 @@
     "Also, in this chapter we saw one example of a format specifier. For more information, ask \"What format specifiers can be used in a Python f-string?\""
    ]
   },
-  {
-   "cell_type": "markdown",
-   "id": "c85eab62",
-   "metadata": {},
-   "source": [
-    "## Exercises\n"
-   ]
-  },
   {
    "cell_type": "markdown",
    "id": "bcdab7d6",

_sources/chap15.ipynb

@@ -1129,9 +1129,9 @@
     "\n",
     "2. Write an `__init__` method that takes `year`, `month`, and `day` as parameters and assigns the parameters to attributes. Create an object that represents June 22, 1933.\n",
     "\n",
-    "2. Write `__str__` method that uses an f-string to format the attributes and returns the result. If you test it with the `Date` you created, the result should be `1933-06-22`.\n",
+    "3. Write `__str__` method that uses an f-string to format the attributes and returns the result. If you test it with the `Date` you created, the result should be `1933-06-22`.\n",
     "\n",
-    "3. Write a method called `is_after` that takes two `Date` objects and returns `True` if the first comes after the second. Create a second object that represents September 17, 1933, and check whether it comes after the first object.\n",
+    "4. Write a method called `is_after` that takes two `Date` objects and returns `True` if the first comes after the second. Create a second object that represents September 17, 1933, and check whether it comes after the first object.\n",
     "\n",
     "Hint: You might find it useful write a method called `to_tuple` that returns a tuple that contains the attributes of a `Date` object in year-month-day order."
    ]