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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 is_valid(self, csdl):
 """ Checks if the given CSDL is valid. Uses API documented at http://dev.datasift.com/docs/api/rest-api/endpoints/validate :param csdl: CSDL to validate :type csdl: str :returns: Boolean indicating the validity of the CSDL :rtype: bool :raises: :class:`~datasift.exceptions.DataSiftApiException`, :class:`requests.exceptions.HTTPError` """

        try:
            self.validate(csdl)
        except DataSiftApiException as e:
            if e.response.status_code == 400:
                return False
            else:
                raise e
        return True