          'invalid': _('"{input}" is not a valid boolean.')
      }
      default_empty_html = False
      initial = False
      TRUE_VALUES = set(('t', 'T', 'true', 'True', 'TRUE', '1', 1, True))
      FALSE_VALUES = set(('f', 'F', 'false', 'False', 'FALSE', '0', 0, 0.0, False))
  
      def __init__(self, **kwargs):
          assert 'allow_null' not in kwargs, '`allow_null` is not a valid option. Use `NullBooleanField` instead.'
          super(BooleanField, self).__init__(**kwargs)
  
 
</s> remove     TRUE_VALUES = set(('t', 'T', 'true', 'True', 'TRUE', '1', 1, True))
    FALSE_VALUES = set(('f', 'F', 'false', 'False', 'FALSE', '0', 0, 0.0, False))
    NULL_VALUES = set(('n', 'N', 'null', 'Null', 'NULL', '', None))
 </s> add     TRUE_VALUES = {'t', 'T', 'true', 'True', 'TRUE', '1', 1, True}
    FALSE_VALUES = {'f', 'F', 'false', 'False', 'FALSE', '0', 0, 0.0, False}
    NULL_VALUES = {'n', 'N', 'null', 'Null', 'NULL', '', None} </s> remove         ])
 </s> add         } </s> remove         ])
 </s> add         } </s> remove         missing = dict([
            (field_name, self.missing_message)
 </s> add         missing = {
            field_name: self.missing_message </s> remove         list_kwargs.update(dict([
            (key, value) for key, value in kwargs.items()
 </s> add         list_kwargs.update({
            key: value for key, value in kwargs.items()
    TRUE_VALUES = {'t', 'T', 'true', 'True', 'TRUE', '1', 1, True}
    FALSE_VALUES = {'f', 'F', 'false', 'False', 'FALSE', '0', 0, 0.0, False}
          'invalid': _('"{input}" is not a valid boolean.')
      }
      default_empty_html = False
      initial = False
    TRUE_VALUES = {'t', 'T', 'true', 'True', 'TRUE', '1', 1, True}
    FALSE_VALUES = {'f', 'F', 'false', 'False', 'FALSE', '0', 0, 0.0, False}
    TRUE_VALUES = {'t', 'T', 'true', 'True', 'TRUE', '1', 1, True}
    FALSE_VALUES = {'f', 'F', 'false', 'False', 'FALSE', '0', 0, 0.0, False}
  
      def __init__(self, **kwargs):
          assert 'allow_null' not in kwargs, '`allow_null` is not a valid option. Use `NullBooleanField` instead.'
          super(BooleanField, self).__init__(**kwargs)
  
keep keep keep keep replace replace keep keep keep keep keep
 Replaced all dict and set conversions from lists to dict and set literals. 
rest_framework/fields.py