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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def validate_wrap(self, value):
        ''' Checks that ``value`` is an instance of ``DocumentField.type``.
            if it is, then validation on its fields has already been done and
            no further validation is needed.
        '''
        if not isinstance(value, self.type):
            self._fail_validation_type(value, self.type)