              self.validators.append(ArrayMaxLengthValidator(int(max_length)))
  
      def prepare_value(self, value):
          if isinstance(value, list):
              return self.delimiter.join(six.text_type(self.base_field.prepare_value(v)) for v in value)
          return value
  
      def to_python(self, value):
          if isinstance(value, list):
              items = value
 
</s> remove         if isinstance(value, six.string_types) or value is None:
 </s> add         if isinstance(value, str) or value is None: </s> remove         if isinstance(value, six.string_types):
 </s> add         if isinstance(value, str): </s> remove         if isinstance(value, six.string_types):
 </s> add         if isinstance(value, str): </s> remove         if isinstance(value, six.string_types):
 </s> add         if isinstance(value, str): </s> remove         if isinstance(value, six.text_type):
            return six.memoryview(b64decode(force_bytes(value)))
 </s> add         if isinstance(value, str):
            return memoryview(b64decode(force_bytes(value)))
            return self.delimiter.join(str(self.base_field.prepare_value(v)) for v in value)
              self.validators.append(ArrayMaxLengthValidator(int(max_length)))
  
      def prepare_value(self, value):
          if isinstance(value, list):
            return self.delimiter.join(str(self.base_field.prepare_value(v)) for v in value)
          return value
  
      def to_python(self, value):
          if isinstance(value, list):
              items = value
keep keep keep keep replace keep keep keep keep keep
 Refs #23919 -- Removed six.<various>_types usage

Thanks Tim Graham and Simon Charette for the reviews. 
django/contrib/postgres/forms/array.py