diff --git a/sacredboard/app/data/filesdao.py b/sacredboard/app/data/filesdao.py
index 4a96896..4b79798 100644
--- a/sacredboard/app/data/filesdao.py
+++ b/sacredboard/app/data/filesdao.py
@@ -1,12 +1,8 @@
-"""
-Interface for accessing Sacred files.
-"""
+"""Interface for accessing Sacred files."""
 
 
 class FilesDAO:
-    """
-    Interface for accessing files.
-    """
+    """Interface for accessing files."""
 
     def get(self, file_id):
         """
diff --git a/sacredboard/app/webapi/files.py b/sacredboard/app/webapi/files.py
index 5ca5b0f..c480470 100644
--- a/sacredboard/app/webapi/files.py
+++ b/sacredboard/app/webapi/files.py
@@ -35,7 +35,7 @@ def _get_binary_info(binary: bytes):
             hex_data += " "
         hex_data += hex(binary[i])
     hex_data += " ..."
-    return f"Binary data\nLength: {len(binary)}\nFirst 10 bytes: {hex_data}"
+    return "Binary data\nLength: {}\nFirst 10 bytes: {}".format(len(binary), hex_data)
 
 
 def get_file(file_id: str, download):
@@ -85,7 +85,7 @@ def get_files_zip(run_id: int, filetype: _FileType):
         for f in target_files:
             # source and artifact files use a different data structure
             file_id = f['file_id'] if 'file_id' in f else f[1]
-            file: gridfs.GridOut = dao_files.get(file_id)
+            file = dao_files.get(file_id)
             data = zipfile.ZipInfo(file.filename, date_time=file.upload_date.timetuple())
             data.compress_type = zipfile.ZIP_DEFLATED
             zf.writestr(data, file.read())