diff --git a/src/H5ChunkedWriter.cpp b/src/H5ChunkedWriter.cpp
index 81888c1..69d6dbb 100644
--- a/src/H5ChunkedWriter.cpp
+++ b/src/H5ChunkedWriter.cpp
@@ -187,41 +187,6 @@ hsize_t HDF5ChunkedWriter::prepare_storage_for_frame(size_t frame_index, size_t*
     return relative_frame_index;
 }
 
-void HDF5ChunkedWriter::write_format_data(H5::CommonFG& file_node, h5_parent& format_node, std::map<std::string, h5_value>& values){
-    auto node_group = h5_utils::create_group(file_node, format_node.name);
-
-    for (auto item : format_node.items) {
-
-        if (item->node_type == GROUP) {
-            auto sub_group = dynamic_cast<h5_group*>(item); 
-
-            write_format_data(node_group, *sub_group, values);
-        } else if (item->node_type == ATTRIBUTE) {
-            auto sub_attribute = dynamic_cast<h5_attr*>(item);
-
-            h5_utils::write_attribute(node_group, *sub_attribute, values);
-        } else if (item->node_type == DATASET) {
-            auto sub_dataset = dynamic_cast<h5_dataset*>(item);
-
-            auto current_dataset = h5_utils::write_dataset(node_group, *sub_dataset, values);
-
-            for (auto dataset_attr : sub_dataset->items) {
-                // You can specify only attributes inside a dataset.
-                if (dataset_attr->node_type != ATTRIBUTE) {
-                    stringstream error_message;
-                    error_message << "Invalid element " << dataset_attr->name << " on dataset " << sub_dataset->name << ". Only attributes allowd.";
-
-                    throw invalid_argument( error_message.str() );
-                }
-
-                auto sub_attribute = dynamic_cast<h5_attr*>(item);
-
-                h5_utils::write_attribute(current_dataset, *sub_attribute, values);
-            }
-        }
-    }
-}
-
 void HDF5ChunkedWriter::write_format(h5_group& format_root, std::map<std::string, h5_value>& values) {
-    write_format_data(file, format_root, values);
+    h5_utils::write_format_data(file, format_root, values);
 }
\ No newline at end of file
diff --git a/src/H5ChunkedWriter.hpp b/src/H5ChunkedWriter.hpp
index c856cba..656e132 100644
--- a/src/H5ChunkedWriter.hpp
+++ b/src/H5ChunkedWriter.hpp
@@ -31,8 +31,6 @@ class HDF5ChunkedWriter
     hsize_t prepare_storage_for_frame(size_t frame_index, size_t* frame_shape);
     void create_file(size_t* frame_shape, hsize_t frame_chunk=0);
 
-    void write_format_data(H5::CommonFG& file_node, h5_parent& format_node, std::map<std::string, h5_value>& values);
-
     public:
         HDF5ChunkedWriter(const std::string filename, const std::string dataset_name, hsize_t frames_per_file=0, hsize_t initial_dataset_size=config::initial_dataset_size);
         ~HDF5ChunkedWriter();
diff --git a/src/h5_utils.cpp b/src/h5_utils.cpp
index a565013..8bbc9be 100644
--- a/src/h5_utils.cpp
+++ b/src/h5_utils.cpp
@@ -224,4 +224,39 @@ void h5_utils::write_attribute(H5::H5Object& target, h5_attr& attribute, map<str
 
         throw runtime_error(error_message.str());
     }
+}
+
+void h5_utils::write_format_data(H5::CommonFG& file_node, h5_parent& format_node, std::map<std::string, h5_value>& values){
+    auto node_group = h5_utils::create_group(file_node, format_node.name);
+
+    for (auto item : format_node.items) {
+
+        if (item->node_type == GROUP) {
+            auto sub_group = dynamic_cast<h5_group*>(item); 
+
+            write_format_data(node_group, *sub_group, values);
+        } else if (item->node_type == ATTRIBUTE) {
+            auto sub_attribute = dynamic_cast<h5_attr*>(item);
+
+            h5_utils::write_attribute(node_group, *sub_attribute, values);
+        } else if (item->node_type == DATASET) {
+            auto sub_dataset = dynamic_cast<h5_dataset*>(item);
+
+            auto current_dataset = h5_utils::write_dataset(node_group, *sub_dataset, values);
+
+            for (auto dataset_attr : sub_dataset->items) {
+                // You can specify only attributes inside a dataset.
+                if (dataset_attr->node_type != ATTRIBUTE) {
+                    stringstream error_message;
+                    error_message << "Invalid element " << dataset_attr->name << " on dataset " << sub_dataset->name << ". Only attributes allowd.";
+
+                    throw invalid_argument( error_message.str() );
+                }
+
+                auto sub_attribute = dynamic_cast<h5_attr*>(item);
+
+                h5_utils::write_attribute(current_dataset, *sub_attribute, values);
+            }
+        }
+    }
 }
\ No newline at end of file
diff --git a/src/h5_utils.hpp b/src/h5_utils.hpp
index a5e67bf..30631ce 100644
--- a/src/h5_utils.hpp
+++ b/src/h5_utils.hpp
@@ -3,9 +3,10 @@
 
 #include <string>
 #include <list>
+#include <map>
+
 #include <boost/any.hpp>
 #include <H5Cpp.h>
-#include <map>
 
 typedef boost::any h5_value;
 
@@ -81,6 +82,8 @@ namespace h5_utils{
     void write_attribute(H5::H5Object& target, std::string name, int value);
 
     boost::any get_value_from_reference(std::string& dataset_name, boost::any value_reference, std::map<std::string, boost::any>& values);
+
+    void write_format_data(H5::CommonFG& file_node, h5_parent& format_node, std::map<std::string, h5_value>& values);
 }
 
 #endif
\ No newline at end of file