Fixed a few typos!

modern_2_method_chaining.ipynb

@@ -283,7 +283,7 @@
     "    return df\n",
     "```\n",
     "\n",
-    "This plays nicely with [`engarde`](http://engarde.readthedocs.org), a little library I wrote to validate data as it flows through the pipeline (it essentialy turns those logging statements into excpetions if something looks wrong)."
+    "This plays nicely with [`engarde`](http://engarde.readthedocs.org), a little library I wrote to validate data as it flows through the pipeline (it essentially turns those logging statements into exceptions if something looks wrong)."
    ]
   },
   {
@@ -300,7 +300,7 @@
     "Second, I suspect people have a mental model of `inplace` operations happening, you know, inplace. That is, extra memory doesn't need to be allocated for the result. [But that might not actually be true](http://stackoverflow.com/a/22533110).\n",
     "Quoting Jeff Reback from that answer\n",
     "\n",
-    "> Their is **no guarantee** that an inplace operation is actually faster. Often they are actually the same operation that works on a copy, but the top-level reference is reassigned.\n",
+    "> There is **no guarantee** that an inplace operation is actually faster. Often they are actually the same operation that works on a copy, but the top-level reference is reassigned.\n",
     "\n",
     "That is, the pandas code might look something like this\n",
     "\n",