E701: Invalid type for len()

[ricvillagrana]

After doing :PluginUpdate, I started seeing this error message each time I used the autocomplete function of emmet using Nvim.

Error detected while processing function emmet#expandAbbr[1]..emmet#getFileType:
line   61:
E701: Invalid type for len()
Press ENTER or type command to continue

[kmoschcau]

This looks like a duplicate of #559.