diff --git a/HowBadIsMyBatch.ipynb b/HowBadIsMyBatch.ipynb
index 271895ee9be..31723058d59 100644
--- a/HowBadIsMyBatch.ipynb
+++ b/HowBadIsMyBatch.ipynb
@@ -34,22 +34,17 @@
     "    dataFrames = map(createDataFrameFromDescr, vaersDescrs)\n",
     "    return pd.concat(dataFrames)\n",
     "\n",
+    "def filterDataFrame(df, manufacturer = None, dose = None):\n",
+    "    isCovid19 = df[\"VAX_TYPE\"] == \"COVID19\"\n",
+    "    isManufacturer = df[\"VAX_MANU\"] == manufacturer if manufacturer is not None else True\n",
+    "    isDose = df[\"VAX_DOSE_SERIES\"].str.contains(dose) if dose is not None else True\n",
+    "    return df[isCovid19 & isManufacturer & isDose]\n",
+    "\n",
     "def createAndFilterDataFrameFromDescrs(vaersDescrs, manufacturer, dose):\n",
-    "    def filterDataFrame(df):\n",
-    "        return df[\n",
-    "            (df[\"VAX_TYPE\"] == \"COVID19\") &\n",
-    "            (df[\"VAX_MANU\"] == manufacturer) &\n",
-    "            (df[\"VAX_DOSE_SERIES\"].str.contains(dose))]\n",
-    "    \n",
-    "    return filterDataFrame(createDataFrameFromDescrs(vaersDescrs))\n",
+    "    return filterDataFrame(createDataFrameFromDescrs(vaersDescrs), manufacturer = manufacturer, dose = dose)\n",
     "\n",
     "def createDataFrameSevereEffectsFromDescrs(vaersDescrs, dose):\n",
-    "    def filterDataFrame(df):\n",
-    "        return df[\n",
-    "            (df[\"VAX_TYPE\"] == \"COVID19\") &\n",
-    "            (df[\"VAX_DOSE_SERIES\"].str.contains(dose))]\n",
-    "\n",
-    "    return filterDataFrame(createDataFrameFromDescrs(vaersDescrs))"
+    "    return filterDataFrame(createDataFrameFromDescrs(vaersDescrs), dose = dose)"
    ]
   },
   {
@@ -122,6 +117,7 @@
     "def createCompanyByBatchCodeTable(df):\n",
     "    return createManufacturerByBatchCodeTable(df).rename(columns = {\"VAX_MANU\": \"COMPANY\"})\n",
     "\n",
+    "# create table from https://www.howbadismybatch.com/combined.html\n",
     "def createSevereEffectsBatchCodeTable(df):\n",
     "    def filterDataFrame(df, col):\n",
     "        return df[df[col] == 'Y']['VAX_LOT']\n",