diff --git a/dataset/src/main/openapi/dataset.yaml b/dataset/src/main/openapi/dataset.yaml
index d196b3e4e..714095b80 100644
--- a/dataset/src/main/openapi/dataset.yaml
+++ b/dataset/src/main/openapi/dataset.yaml
@@ -1003,6 +1003,7 @@ components:
 
     DatasetPartFiles:
       type: array
+      nullable: true
       description: |
         Notes:
           - Each parts defined in dataset should have a file defined in this list
diff --git a/openapi/templates/.gitkeep b/openapi/templates/.gitkeep
new file mode 100644
index 000000000..e69de29bb
diff --git a/openapi/templates/optionalDataType.mustache b/openapi/templates/optionalDataType.mustache
deleted file mode 100644
index 41cf78ad0..000000000
--- a/openapi/templates/optionalDataType.mustache
+++ /dev/null
@@ -1 +0,0 @@
-{{^isFile}}{{{dataType}}}{{^required}}{{^defaultValue}}?{{/defaultValue}}{{/required}}{{/isFile}}{{#isFile}}{{#isArray}}Array<{{/isArray}}org.springframework.web.multipart.MultipartFile{{#isArray}}>{{/isArray}}{{^required}}?{{/required}}{{/isFile}}
\ No newline at end of file