diff --git a/src/hdf5_lib.py b/src/hdf5_lib.py
index fc55723..3bae37c 100644
--- a/src/hdf5_lib.py
+++ b/src/hdf5_lib.py
@@ -13,7 +13,7 @@ import instruments.readers.filereader_registry as filereader_registry
 
  
    
-def transfer_file_dict_to_hdf5(h5file, group_name, file_dict):
+def __transfer_file_dict_to_hdf5(h5file, group_name, file_dict):
     """
     Transfers data from a file_dict to an HDF5 file.
 
@@ -68,7 +68,7 @@ def transfer_file_dict_to_hdf5(h5file, group_name, file_dict):
         print(inst) 
         logging.error('Failed to transfer data into HDF5: %s', inst)
 
-def copy_file_in_group(source_file_path, dest_file_obj : h5py.File, dest_group_name, work_with_copy : bool = True):
+def __copy_file_in_group(source_file_path, dest_file_obj : h5py.File, dest_group_name, work_with_copy : bool = True):
     # Create copy of original file to avoid possible file corruption and work with it.
 
     if work_with_copy:
@@ -191,7 +191,7 @@ def create_hdf5_file_from_filesystem_path(path_to_input_directory: str,
                     #file_dict = ext_to_reader_dict[file_ext](os.path.join(dirpath,filename))
                     file_dict = filereader_registry.select_file_reader(dest_group_name)(os.path.join(dirpath,filename))
 
-                    transfer_file_dict_to_hdf5(h5file, group_name, file_dict)
+                    __transfer_file_dict_to_hdf5(h5file, group_name, file_dict)
                     
                 else:
                     source_file_path = os.path.join(dirpath,filename)
@@ -199,7 +199,7 @@ def create_hdf5_file_from_filesystem_path(path_to_input_directory: str,
                      #group_name +'/'+filename
                     #ext_to_reader_dict[file_ext](source_file_path, dest_file_obj, dest_group_name)
                     #g5505f_reader.select_file_reader(dest_group_name)(source_file_path, dest_file_obj, dest_group_name)
-                    copy_file_in_group(source_file_path, dest_file_obj, dest_group_name, False)
+                    __copy_file_in_group(source_file_path, dest_file_obj, dest_group_name, False)
 
             # Update the progress bar and log the end message
             utils.progressBar(dir_number, number_of_dirs, end_message)
@@ -286,6 +286,6 @@ def save_processed_dataframe_to_hdf5(df, annotator, output_filename): # src_hdf5
     with h5py.File(output_filename, mode) as h5file:
         # Add project level attributes at the root/top level
         h5file.attrs.update(project_level_attributes)
-        transfer_file_dict_to_hdf5(h5file, '/', file_dict)
+        __transfer_file_dict_to_hdf5(h5file, '/', file_dict)
 
 #if __name__ == '__main__':