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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 _get_crl_url(self, distribution_points):
 """ Grabs the first URL out of a asn1crypto.x509.CRLDistributionPoints object :param distribution_points: The x509.CRLDistributionPoints object to pull the URL out of :return: A unicode string or None """


        if distribution_points is None:
            return None

        for distribution_point in distribution_points:
            name = distribution_point['distribution_point']
            if name.name == 'full_name' and name.chosen[0].name == 'uniform_resource_identifier':
                return name.chosen[0].chosen.native

        return None