diff --git a/src/util.rs b/src/util.rs
index cc48488..da4f8d6 100644
--- a/src/util.rs
+++ b/src/util.rs
@@ -63,6 +63,18 @@ impl DF {
         }
     }
 }
+trait DFS {
+    fn lazy(self) -> Vec<LazyFrame>;
+    fn collect(self) -> Vec<DataFrame>;
+}
+impl DFS for Vec<DF> {
+    fn lazy(self) -> Vec<LazyFrame> {
+        self.into_iter().map(|df| df.lazy()).collect()
+    }
+    fn collect(self) -> Vec<DataFrame> {
+        self.into_iter().map(|df| df.collect().unwrap()).collect()
+    }
+}
 
 pub enum Source {
     Read,
@@ -77,7 +89,7 @@ struct Ark {
 impl Ark {
     pub fn new(source: Source, ticker: Ticker) -> Result<Self, Box<dyn Error>> {
         let mut ark = Self {
-            df: Self::read_parquet(ticker)?.into(),
+            df: Self::read_parquet(ticker)?,
             ticker,
         };
 
@@ -98,12 +110,18 @@ impl Ark {
         };
 
         if let Some(update) = update {
-            ark.df = Self::concat_df(vec![ark.df, update.into()])?.into();
+            ark.df = Self::concat_df(vec![
+                Self::df_format(ark.df)?,
+                Self::df_format(update.into())?,
+            ])?
+            .into();
         }
         Ok(ark)
     }
 
-    pub fn write_parquet(mut self) -> Result<Self, Box<dyn Error>> {
+    pub fn write_parquet(&self) -> Result<&Self, Box<dyn Error>> {
+        // with format
+        self = self.format()?;
         ParquetWriter::new(File::create(format!(
             "data/parquet/{}.parquet",
             self.ticker
@@ -112,34 +130,44 @@ impl Ark {
         Ok(self)
     }
 
-    pub fn df_sort(&self) -> Result<&Self, Box<dyn Error>> {
-        let df = self
-            .df
-            .collect()?
-            .sort(["date", "weight"], vec![false, true])?;
-        self.df = df.into();
+    fn sort(&self) -> Result<&Self, Box<dyn Error>> {
+        self.df = Self::df_sort(self.df)?;
         Ok(self)
     }
 
-    fn read_parquet(ticker: Ticker) -> Result<LazyFrame, Box<dyn Error>> {
+    fn df_sort(df: DF) -> Result<DF, Box<dyn Error>> {
+        let df = df.collect()?.sort(["date", "weight"], vec![false, true])?;
+        Ok(df.into())
+    }
+
+    fn read_parquet(ticker: Ticker) -> Result<DF, Box<dyn Error>> {
         let df = LazyFrame::scan_parquet(
             format!("data/parquet/{}.parquet", ticker),
             ScanArgsParquet::default(),
         )?;
-        Ok(df)
-    }
-
-    fn concat_df(mut dfs: Vec<DF>) -> Result<DF, Box<dyn Error>> {
-        // with dedupe and format
-        // for x in &mut dfs {
-        //     *x = Self::df_format(x.to_owned())?.lazy();
-        // }
-        let mut df = concat(dfs, false, true)?;
-        df = df.unique_stable(None, UniqueKeepStrategy::First);
         Ok(df.into())
     }
 
-    fn df_format(df: LazyFrame) -> Result<DataFrame, Box<dyn Error>> {
+    fn concat_df(mut dfs: Vec<DF>) -> Result<DF, Box<dyn Error>> {
+        // with dedupe
+        let mut df = concat(dfs.lazy(), false, true)?;
+        Ok(Self::dedupe(df.into())?)
+    }
+
+    pub fn dedupe(mut df: DF) -> Result<DF, Box<dyn Error>> {
+        df = df
+            .lazy()
+            .unique_stable(None, UniqueKeepStrategy::First)
+            .into();
+        Ok(df)
+    }
+
+    pub fn format(&self) -> Result<&Self, Box<dyn Error>> {
+        self.df = Self::df_format(self.df)?.into();
+        Ok(self)
+    }
+
+    fn df_format(df: DF) -> Result<DF, Box<dyn Error>> {
         let mut df = df.collect()?;
 
         if df.get_column_names().contains(&"market_value_($)") {
@@ -267,11 +295,11 @@ impl Ark {
             df = df.select(["date", "ticker", "cusip", "company", "weight"])?;
         }
 
-        Ok(df)
+        Ok(df.into())
     }
 
     pub fn get_api(self, last_day: Option<NaiveDate>) -> Result<LazyFrame, Box<dyn Error>> {
-        let tic = self.ticker;
+        let tic: Ticker = self.ticker;
         let url = match (tic, last_day) {
             (self::Ticker::ARKVC, Some(last_day)) => format!(
                 "https://api.nexveridian.com/arkvc_holdings?end={}",
@@ -301,22 +329,22 @@ impl Ark {
         Reader::Csv.get_data_url(url)
     }
 
-    pub fn merge_old_csv_to_parquet(ticker: Ticker) -> Result<(), Box<dyn Error>> {
+    pub fn merge_old_csv_to_parquet(ticker: Ticker) -> Result<&'static Self, Box<dyn Error>> {
         let mut dfs = vec![];
         for x in glob(&format!("data/csv/{}/*", ticker))?.filter_map(Result::ok) {
             dfs.push(LazyCsvReader::new(x).finish()?);
         }
-        let mut df = concat(dfs, false, true)?;
+        let mut df = concat(dfs, false, true)?.into();
 
-        if Self::read_parquet(ticker).is_ok() {
+        let ark = if Self::read_parquet(ticker).is_ok() {
             let df_old = Self::read_parquet(ticker)?;
-            df = Self::concat_df(vec![df_old, df])?;
-            write_parquet(ticker, df_sort(df.collect()?)?)?;
+            df = Self::concat_df(vec![Self::df_format(df_old)?, Self::df_format(df)?])?;
+            Self { df, ticker }.sort()?.write_parquet()?
         } else {
-            write_parquet(ticker, df_format(df)?)?;
-        }
+            Self { df, ticker }.sort()?.write_parquet()?
+        };
 
-        Ok(())
+        Ok(ark)
     }
 }