raise Value Error('Custom files must have an attribution') in folium

[Kofi Anane Poku]

Please add a code sample or a nbviewer link, copy-pastable if possible

# Your code here

Problem description

[this should explain why the current behavior is a problem and what is the expected output.]

Expected Output

Output of folium.__version__

[Frank Anema]

Dupe of #1900

[Kofi Anane Poku]

Dupe of #1900

Alright. Thank you