Return a current membership for this org, or, None if
        there is none.

def get_current_membership_for_org(self, account_num, verbose=False):
        """Return a current membership for this org, or, None if
        there is none.
        """
        all_memberships = self.get_memberships_for_org(
            account_num=account_num,
            verbose=verbose)
        # Look for first membership that hasn't expired yet.
        for membership in all_memberships:
            if (membership.expiration_date and
                membership.expiration_date > datetime.datetime.now()):  # noqa
                return membership  # noqa
        return None