Dynamic SelectField choices when using FieldList (Python wtforms)

Question

I am using wtforms (version 2.3) and need to have a series of SelectField instances in my form. The choices for this repeated select field need to be dynamically supplied. I cannot figure out how to add the choices to the SelectField rather than the FieldList.

The code below reflects what I'm doing. I've confirmed that get_wtforms_people_for is returning a choice as a list of tuples appropriate for wtforms choices. However, form.people() in my output html renders without any choices.

     class CompanySelectForm(Form):

        company = SelectField('Company', validators=[validators.DataRequired()])
        people = FieldList(SelectField(''), min_entries=1)

     def get_form(company_name):

        form = CompanySelectForm(data={'company': company_name})
        if company_name:
            # The following line runs, but does not produce any choices in output.
            form.people.choices = get_wtforms_people_for(company_name)

        return form