diff --git a/README.md b/README.md
index 4770e1d..c4e90e9 100644
--- a/README.md
+++ b/README.md
@@ -88,9 +88,16 @@ mpc = m.loadcase('case9')
 mpopt = m.mpoption('verbose', 2)
 m.push("_mpopt", mpopt)
 m.push("_mpc", mpc, verbose=False)
+
 m.eval("_r1 = runopf(_mpc, _mpopt);", verbose=False)
-m.eval("_r1.raw = rmfield(_r1.raw, 'task');")
-m.eval("_r1 = rmfield(_r1, 'om');")
+
+# `_r1` containts unsupported `<object opf_model>`, needs to be removed first
+m.eval(
+    """
+    _r1.raw = rmfield(_r1.raw, 'task');
+    _r1 = rmfield(_r1, 'om');
+    """
+)
 mpc = m.pull("_r1")
 ```
 
@@ -103,19 +110,20 @@ from matpower import start_instance
 # start instance
 m = start_instance()
 
-# use octave native to run some commands
-m.eval("mpopt = mpoption('verbose', 2);")
-m.eval("mpc = loadcase('case9');")
-m.eval("r1 = runopf(mpc, mpopt);") # we avoid parse `r1` that containts unsupported `<object opf_model>`
+m.eval(
+    """
+    mpopt = mpoption('verbose', 2);
+    mpc = loadcase('case9');
+    _r1 = runopf(mpc, mpopt);
+    """
+)
 
 # fech data to python (.eval is used because .pull is not working in acessing field)
-r1_mpc = {}
-r1_mpc['baseMVA'] = m.eval('r1.baseMVA;')
-r1_mpc['version'] = m.eval('r1.version;')
-r1_mpc['bus'] = m.eval('r1.bus;')
-r1_mpc['gen'] = m.eval('r1.gen;')
-r1_mpc['branch'] = m.eval('r1.branch;')
-r1_mpc['gencost'] = m.eval('r1.gencost;')
+r1_mpc = m.eval(
+    "struct("
+    " 'baseMVA', _r1.baseMVA, 'version', _r1.version, 'bus', _r1.bus, 'gen', _r1.gen,"
+    " 'branch', _r1.branch, 'gencost', _r1.gencost);"
+)
 
 # modify variable if necessary
 [GEN_BUS, PG, QG, QMAX, QMIN, VG, MBASE, GEN_STATUS, PMAX, PMIN, MU_PMAX, 
@@ -141,7 +149,7 @@ m.push('mpc', r1_mpc) # push r1_mpc in python to mpc in octave
 mpc = m.pull('mpc')
 
 # test if our pushed variable can be used
-m.eval("r1 = runopf(mpc, mpopt);")
+m.eval("_r1 = runopf(mpc, mpopt);")
 ```
 
 `matpower-pip` also support using `matlab.engine`.
@@ -162,22 +170,23 @@ mpc = m.runpf('case5', nargout=0)
     Impacted case:
 
     ```python
-    r1 = m.runopf(mpc)
+    _r1 = m.runopf(mpc)
     ```
 
     Solution:
 
     ```python
     m.push('mpc', mpc)
-    m.eval("r1 = runopf(mpc, mpopt);")
-
-    r1_mpc = {}
-    r1_mpc['baseMVA'] = m.eval('r1.baseMVA;')
-    r1_mpc['version'] = m.eval('r1.version;')
-    r1_mpc['bus'] = m.eval('r1.bus;')
-    r1_mpc['gen'] = m.eval('r1.gen;')
-    r1_mpc['branch'] = m.eval('r1.branch;')
-    r1_mpc['gencost'] = m.eval('r1.gencost;')
+    r1_mpc = m.eval(
+        """
+        mpopt = mpoption('verbose', 2);
+        _r1 = runopf(mpc, mpopt);
+        """
+
+        "struct("
+        " 'baseMVA', _r1.baseMVA, 'version', _r1.version, 'bus', _r1.bus, 'gen', _r1.gen,"
+        " 'branch', _r1.branch, 'gencost', _r1.gencost);"
+    )
     ```
 
 ## Versioning
diff --git a/notebooks/runuopf.ipynb b/notebooks/runuopf.ipynb
new file mode 100644
index 0000000..ce86b8d
--- /dev/null
+++ b/notebooks/runuopf.ipynb
@@ -0,0 +1,164 @@
+{
+ "cells": [
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# install octave\n",
+    "!sudo apt-get -qq update\n",
+    "!sudo apt-get -qq install octave octave-signal liboctave-dev\n",
+    "\n",
+    "# install oct2py that compatible with colab\n",
+    "import os\n",
+    "\n",
+    "from pkg_resources import get_distribution\n",
+    "\n",
+    "os.system(\n",
+    "    f\"pip install -qq\"\n",
+    "    f\" ipykernel=={get_distribution('ipykernel').version}\"\n",
+    "    f\" ipython=={get_distribution('ipython').version}\"\n",
+    "    f\" tornado=={get_distribution('tornado').version}\"\n",
+    "    f\" oct2py\"\n",
+    ")\n",
+    "\n",
+    "# install packages\n",
+    "!pip install -qq matpower matpowercaseframes"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "oct2py version: 5.7.2\n",
+      "matpower version: 8.0.0.2.2.2\n"
+     ]
+    }
+   ],
+   "source": [
+    "import oct2py\n",
+    "\n",
+    "import matpower\n",
+    "\n",
+    "print(f\"oct2py version: {oct2py.__version__}\")\n",
+    "print(f\"matpower version: {matpower.__version__}\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "from matpower import start_instance"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "m = start_instance()"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "mpc = m.loadcase(\"case9\")\n",
+    "mpopt = m.mpoption(\"verbose\", 2)\n",
+    "m.push(\"_mpopt\", mpopt)\n",
+    "m.push(\"_mpc\", mpc, verbose=False)\n",
+    "m.eval(\"_r1 = runuopf(_mpc, _mpopt);\", verbose=False)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 6,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# pull all after cleansing unsupported data\n",
+    "m.eval(\n",
+    "    \"\"\"\n",
+    "    _r1.raw = rmfield(_r1.raw, 'task');\n",
+    "    _r1 = rmfield(_r1, 'om');\n",
+    "    \"\"\"\n",
+    ")\n",
+    "mpc = m.pull(\"_r1\")"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 7,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# selective pull\n",
+    "r1_mpc = m.eval(\n",
+    "    \"struct('baseMVA', _r1.baseMVA, 'version', _r1.version, 'bus', _r1.bus,\"\n",
+    "    \" 'gen', _r1.gen, 'branch', _r1.branch, 'gencost', _r1.gencost);\"\n",
+    ")\n",
+    "r1_mpc"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# # NOTE: you also can run like this\n",
+    "# r1_mpc = m.eval(\n",
+    "#     \"\"\"\n",
+    "#     mpopt = mpoption('verbose', 2);\n",
+    "#     mpc = loadcase('case9');\n",
+    "#     _r1 = runuopf(mpc, mpopt);\n",
+    "#     \"\"\"\n",
+    "#\n",
+    "#     \"struct(\"\n",
+    "#     \" 'baseMVA', _r1.baseMVA, 'version', _r1.version, 'bus', _r1.bus, 'gen', _r1.gen,\"\n",
+    "#     \" 'branch', _r1.branch, 'gencost', _r1.gencost);\"\n",
+    "# )\n",
+    "# r1_mpc"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "env",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.12.4"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 2
+}
diff --git a/notebooks/split_branch.ipynb b/notebooks/split_branch.ipynb
index c17e3e1..e061bac 100644
--- a/notebooks/split_branch.ipynb
+++ b/notebooks/split_branch.ipynb
@@ -105,7 +105,13 @@
   {
    "cell_type": "markdown",
    "metadata": {},
-   "source": []
+   "source": [
+    "## Understanding Parallel Line\n",
+    "\n",
+    "$$\n",
+    "Y_{total} = Y_1 + Y_2 + \\dots + Y_n\n",
+    "$$"
+   ]
   },
   {
    "cell_type": "code",
@@ -264,7 +270,8 @@
    "mimetype": "text/x-python",
    "name": "python",
    "nbconvert_exporter": "python",
-   "pygments_lexer": "ipython3"
+   "pygments_lexer": "ipython3",
+   "version": "3.12.4"
   }
  },
  "nbformat": 4,