Django haystack regular uniform

I am trying to create a regular search form using django haystack, I just change from the senator's documentation:

forms.py

from django import forms
from haystack.forms import SearchForm

class DateRangeSearchForm(SearchForm):
    start_date = forms.DateField(required=False)
    end_date = forms.DateField(required=False)

   def search(self):
        # First, store the SearchQuerySet received from other processing.
        sqs = super(DateRangeSearchForm, self).search()

        # Check to see if a start_date was chosen.
        if self.cleaned_data['start_date']:
            sqs = sqs.filter(pub_date__gte=self.cleaned_data['start_date'])

        # Check to see if an end_date was chosen.
        if self.cleaned_data['end_date']:
            sqs = sqs.filter(pub_date__lte=self.cleaned_data['end_date'])

        return sqs

to:

from django import forms
from haystack.forms import HighlightedModelSearchForm

class CustomSearchForm(HighlightedModelSearchForm):
    title   = forms.CharField(max_length = 100, required = False)
    content = forms.CharField(max_length = 100, required = False)
    date_added = forms.DateField(required = False)
    post_by = forms.CharField(max_length = 100, required = False)

    def search(self):
        sqs = super(CustomSearchForm, self).search()
        if self.cleaned_data['post_by']:
            sqs = sqs.filter(content = self.cleaned_data['post_by'])
        if self.cleaned_data['title']:
            sqs = sqs.filter(content = self.cleaned_data['title'])
        if self.cleaned_data['content']:
            sqs = sqs.filter(content = self.cleaned_data['content'])
        if self.cleaned_data['date_added']:
            sqs = sqs.filter(content = self.cleaned_data['date_added']) 
        return sqs

haystack.urls:

urlpatterns = patterns('haystack.views',
    url(r'^$', search_view_factory(view_class = SearchView, form_class = CustomSearchForm), name='haystack_search'),
)

when I go to the url it says: AttributeError at / search /

CustomSearchForm object has no attribute 'cleaned_data'

Can you guys help me? THX

Then I try to comment on the search method, but when I send a word to a custom field, the result is always nothing, only when I send a word to a non-standard field, it can gimme the result that I want, I have already tried To understand this all day, help us to help