是否可以动态分配字段类型- Django表单？

from django import forms

class DynamicForm(forms.Form):
    field_type = forms.ChoiceField(choices=(
        ('char', 'CharField'),
        ('int', 'IntegerField'),
        ('email', 'EmailField'),
    ))
    value = forms.CharField()

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        field_type = self.cleaned_data.get('field_type')
        if field_type == 'char':
            self.fields['value'] = forms.CharField()
        elif field_type == 'int':
            self.fields['value'] = forms.IntegerField()
        elif field_type == 'email':
            self.fields['value'] = forms.EmailField()