added in-memory conversion to hdf5 file; allowed kwargs for excel conversion

utils/df_utils.py

@@ -19,9 +19,15 @@ class DateFrameHolder:
 from io import BytesIO
 
 
-def to_excel_binary(df):
+def to_excel_binary(df, **kwargs):
     with BytesIO() as out:
-        df.to_excel(out)
+        df.to_excel(out, **kwargs)
+        res = out.getvalue()
+    return res
+
+def to_hdf_binary(df, key="df", **kwargs):
+    with BytesIO() as out:
+        df.to_hdf(out, key, **kwargs)
         res = out.getvalue()
     return res