Remove unused imports from Custom Statespace notebook

Author: jessegrabowski

notebooks/Making a Custom Statespace Model.ipynb

@@ -20,12 +20,9 @@
     "numpyro.set_host_device_count(4)\n",
     "\n",
     "import numpy as np\n",
-    "import pandas as pd\n",
     "import matplotlib.pyplot as plt\n",
     "import arviz as az\n",
     "\n",
-    "from datetime import datetime\n",
-    "\n",
     "from pymc_experimental.statespace.core.statespace import PyMCStateSpace\n",
     "import pytensor.tensor as pt\n",
     "import pymc as pm"