Move serializer registration to __init__.py

docs/tutorials/ball-and-stick-1.ipynb

@@ -1065,13 +1065,9 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "import bokeh.plotting as plt\n",
-    "from bokeh.core.serialization import Serializer\n",
     "from bokeh.io import output_notebook\n",
+    "import bokeh.plotting as plt\n",
     "\n",
-    "Serializer.register(\n",
-    "    h.Vector, lambda obj, serializer: [serializer.encode(item) for item in obj]\n",
-    ")\n",
     "output_notebook()"
    ]
   },

docs/tutorials/scripting-neuron-basics.ipynb

@@ -789,26 +789,6 @@
     "output_notebook()"
    ]
   },
-  {
-   "cell_type": "markdown",
-   "metadata": {},
-   "source": [
-    "We also need to register a custom serialization function with Bokeh in order to plot Hoc vectors directly:"
-   ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
-   "source": [
-    "from bokeh.core.serialization import Serializer\n",
-    "\n",
-    "Serializer.register(\n",
-    "    h.Vector, lambda obj, serializer: [serializer.encode(item) for item in obj]\n",
-    ")"
-   ]
-  },
   {
    "cell_type": "markdown",
    "metadata": {},

share/lib/python/neuron/__init__.py

@@ -1836,3 +1836,13 @@ def _mview_html_tree(hlist, inside_mechanisms_in_use=0):
 if _get_ipython() is not None:
     html_formatter = _get_ipython().display_formatter.formatters["text/html"]
     html_formatter.for_type(hoc.HocObject, _hocobj_html)
+
+# in case Bokeh is installed, register a serialization function for hoc.Vector
+try:
+    from bokeh.core.serialization import Serializer
+
+    Serializer.register(
+        h.Vector, lambda obj, serializer: [serializer.encode(item) for item in obj]
+    )
+except ImportError:
+    pass