post minimal reproducible example. I don't know what
sf
is? Probably sf.toPandas().iloc[10:21]
df
common name for pandas.DataFrame
If you can't explain it to a six year old, you don't understand it yourself, Albert Einstein
How to Ask Questions The Smart Way: link and another link
Create MCV example
Debug small programs
How to Ask Questions The Smart Way: link and another link
Create MCV example
Debug small programs