diff --git a/src/io/parquet/write/mod.rs b/src/io/parquet/write/mod.rs
index d2723a4808b..a0040a9a0d7 100644
--- a/src/io/parquet/write/mod.rs
+++ b/src/io/parquet/write/mod.rs
@@ -33,7 +33,7 @@ use crate::types::days_ms;
 use crate::types::i256;
 use crate::types::NativeType;
 
-pub use nested::write_rep_and_def;
+pub use nested::{num_values, write_rep_and_def};
 pub use pages::{to_leaves, to_nested, to_parquet_leaves};
 use parquet2::schema::types::PrimitiveType as ParquetPrimitiveType;
 pub use parquet2::{
diff --git a/src/io/parquet/write/nested/rep.rs b/src/io/parquet/write/nested/rep.rs
index b1bca7bab33..5bec9f323dc 100644
--- a/src/io/parquet/write/nested/rep.rs
+++ b/src/io/parquet/write/nested/rep.rs
@@ -21,6 +21,7 @@ fn iter<'a>(nested: &'a [Nested]) -> Vec<Box<dyn DebugIter + 'a>> {
         .collect()
 }
 
+/// return number values of the nested
 pub fn num_values(nested: &[Nested]) -> usize {
     let pr = match nested.last().unwrap() {
         Nested::Primitive(_, _, len) => *len,