Add file to support py37 in 4_mstis_sampling

Author: dwhswenson

4_mstis_sampling_tutorial.ipynb

@@ -14,9 +14,11 @@
     "* Setting up a path sampling simulation with various move schemes\n",
     "* Visualizing trajectories while the path sampling is running\n",
     "\n",
+    "<!--\n",
     "<div class=\"alert alert-warning\">\n",
     "This notebook is Python 2-only.\n",
-    "</div>"
+    "</div>\n",
+    "-->"
    ]
   },
   {
@@ -25,11 +27,13 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "%matplotlib inline\n",
     "from __future__ import print_function\n",
+    "%matplotlib inline\n",
+    "import sys\n",
     "import openpathsampling as paths\n",
     "import numpy as np\n",
     "\n",
+    "\n",
     "# toy_plot_helpers.py has conveniences for plotting the 2D contour plots, etc.\n",
     "%run ./toy_plot_helpers.py"
    ]
@@ -217,7 +221,20 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "old_store = paths.AnalysisStorage(\"mstis_bootstrap.nc\")"
+    "# some aspects of storage depend on Python version\n",
+    "if sys.version_info > (3,):\n",
+    "    filename = \"mstis_bootstrap_py3.nc\"\n",
+    "else:\n",
+    "    filename = \"mstis_bootstrap_py2.nc\""
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "old_store = paths.AnalysisStorage(filename)"
    ]
   },
   {