title: __init__() got multiple values for keyword argument 'input_formats'
body: <p>forms.py</p>
  
  <pre><code>from django import forms
  
  ACCEPTED_FORMATS = ['%d-%m-%Y', '%d.%m.%Y', '%d/%m/%Y']
  
  class LeaveRequestForm(forms.Form):
      start_date = forms.DateField(input_formats=ACCEPTED_FORMATS)
      end_date = forms.DateField(input_formats=ACCEPTED_FORMATS)
      working_days = forms.IntegerField(min_value=1)
  </code></pre>
  
  <p>I couldn't find any date format that could pass form validation, every time I received 'Enter a valid date.', so when I tried to define some the exception came out:</p>
  
  <pre><code>__init__() got multiple values for keyword argument 'input_formats'
  </code></pre>
  
  <p><a href="https://docs.djangoproject.com/en/1.8/ref/forms/fields/#datefield" rel="nofollow noreferrer">https://docs.djangoproject.com/en/1.8/ref/forms/fields/#datefield</a></p>
  
  <p>settings.py</p>
  
  <p>...</p>
  
  <pre><code>USE_I18N = True
  
  USE_L10N = True
  </code></pre>
  
  <p>...</p>
  
  <p>I also tried built-in SelectDateWidget with no luck, every time produced invalid date. Maybe there is some "cache" issue:
  <a href="https://stackoverflow.com/questions/27830901/enter-a-valid-date-error-in-django-forms-datefield">&quot;Enter a valid date&quot; Error in Django Forms DateField</a></p>
  
  <p>What should I do to get past this validation checks and move on with proper dates? Are the docs missing something with an error I encountered?</p>