An "Extended" version of WTForms SelectField that allows for nested select options via <optgroup>
Code loosely based on https://gist.github.com/playpauseandstop/1590178
An "Extended" version of WTForms SelectField that allows for nested select options via <optgroup>
Code loosely based on https://gist.github.com/playpauseandstop/1590178