django - ValueError when using ChoiceField -

i want create django form allows users select options dropdown menu, getting value error:

valueerror: need more 1 value unpack

form:

class dropdownform(forms.form):   def __init__(self,*args,**kwargs):     choices = kwargs.pop('choices')     label = kwargs.pop('label')      super(dropdownform,self).__init__(*args,**kwargs)     self.fields['selected'].label = mark_safe(label)     self.fields['selected'].choices = choices    selected = forms.choicefield(widget=forms.select(attrs={'class':"form-control text-center"})) 

view.py:

form_rate = dropdownform(choices=[("high","high")],label="rate",prefix="rate") form_pass_setup = dropdownform(choices=[("auto","auto"),("manual","manual")],label="pass setup",prefix="pass_setup") form_dict.update({'form_rate':form_rate,'form_pass_setup':form_pass_setup})  return render(request,'nominal.html',form_dict) 

template:

<form action="/interfaceapp/nominal_request/" method="post" class="form">   {% csrf_token %}   <div class="panel-body text-center">     <div class="row pad_forms">       <div class="col-xs-3">         {% bootstrap_form form_rate %}       </div>       <div class="col-xs-3">         {% bootstrap_form form_pass_setup %}       </div>     </div>     <br><br>     <button type="submit" class="btn btn-primary center-block" value="submit" name="single">       {% bootstrap_icon "fire" %} generate single requests     </button>   </div> </form> 

can tell me why i'm getting value error?

the problem might occur cause have not set required argument choices choicefield.

here link docs: https://docs.djangoproject.com/en/1.8/ref/forms/fields/#choicefield.