set_dataframe results in SettingWithCopyWarning: A value is trying to be set on a copy of a slice from a DataFrame.

[Badrul Alom]

When using the set_dataframe to copy in a Pandas dataframe into Googlesheets one gets the standard Python error:

worksheet.py:1366: SettingWithCopyWarning: 
A value is trying to be set on a copy of a slice from a DataFrame.
Try using .loc[row_indexer,col_indexer] = value instead

See the caveats in the documentation: https://pandas.pydata.org/pandas-docs/stable/user_guide/indexing.html#returning-a-view-versus-a-copy
  df[col] = df[col].astype('unicode').replace('<NA>', nan)

It doesn't impact the end result - the values still get copied but it's not following Python best practice.

To reproduce I believe you can provide any Pandas dataframe to the set_dataframe function.