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ipynb/AdventUtils.ipynb

@@ -335,9 +335,9 @@
     "    \"\"\"`map`, with the result as a list.\"\"\"\n",
     "    return list(map(function, *sequences))\n",
     "\n",
-    "def cat(things: Collection) -> str:\n",
+    "def cat(things: Collection, sep='') -> str:\n",
     "    \"\"\"Concatenate the things.\"\"\"\n",
-    "    return ''.join(map(str, things))\n",
+    "    return sep.join(map(str, things))\n",
     "    \n",
     "cache   = functools.lru_cache(None)\n",
     "Ø       = frozenset() # empty set"