Fix assert in missing_bridges

ipynb/Portmantout.ipynb

@@ -11,7 +11,7 @@
     "A [***portmanteau***](https://en.wikipedia.org/wiki/Portmanteau) is a word that squishes together two words, like  ***mathlete*** = ***math*** + ***athlete***.  Inspired by [**Darius Bacon**](http://wry.me/), I covered this as a programming exercise in my 2012 [**Udacity course**](https://www.udacity.com/course/design-of-computer-programs--cs212). In 2018 I was re-inspired by [**Tom Murphy VII**](http://tom7.org/), who added a new twist:  [***portmantout words***](http://www.cs.cmu.edu/~tom7/portmantout/) ([***tout***](https://www.duolingo.com/dictionary/French/tout/fd4dc453d9be9f32b7efe838ebc87599) from the French for *all*).\n",
     "\n",
     "\n",
-    "Informally, **portmantout** means that you take all the words in a set and mush them together in some order such that each word overlaps the next. More formally. a partmantout of a set of words *W* is a string *S* constructed as follows:\n",
+    "Informally, **portmantout** means that you take all the words in a set and mush them together in some order such that each word overlaps the next. More formally, a partmantout of a set of words *W* is a string *S* constructed as follows:\n",
     "- Make an ordered list *L* that contains all the words in *W*.\n",
     "- It is allowable for a word to appear more than once in *L*.\n",
     "- Every word in *L* (except the first) must *overlap*: it must begin with a prefix that is the same as a suffix of the previous word.\n",
@@ -71,7 +71,7 @@
     "| ajar|arbitrary|ar||*unused word* |-2|\n",
     "| ajar|rabbits|r||*unused word*|-1|\n",
     "| ajar|argot|ar|goths|*one-step bridge* |0|\n",
-    "| ajar|arrow|ar|owlets| *one-step bridge*|1 (r)\n",
+    "| ajar|arrow|ar|owlets| *one-step bridge*|1 (r)|\n",
     "| ajar|rani, iraq|r|quizzed| *two-step bridge*|5 (anira) | \n",
     "\n",
     "Let's go over the examples:\n",
@@ -719,7 +719,9 @@
     "\n",
     "def missing_bridges(W: Wordset) -> list[str]:\n",
     "    \"\"\"What 1-letter-suffix to 1-letter-prefix bridges are missing from W.bridges?\"\"\"\n",
-    "    return [A + B for (A, B) in letter_pairs if B not in W.bridges[A]]"
+    "    return [A + B for (A, B) in letter_pairs if B not in W.bridges[A]]\n",
+    "\n",
+    "assert not missing_bridges(W)"
    ]
   },
   {
@@ -919,7 +921,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "Yes, there is a problem: there are many more words that start with `b`, `f`, `p`, `u`, `u` and `v` than that end with those letters. In the other direction 45% of all words end in `s`, but only a quarter of that number start with `s`. The start:end ratio for `y` is 1:39."
+    "Yes, there is a problem: there are many more words that start with `b`, `f`, `p`, `u`, and `v` than that end with those letters. In the other direction 45% of all words end in `s`, but only a quarter of that number start with `s`. The start:end ratio for `y` is 1:39."
    ]
   },
   {