Verify that a first-ever subdomain record is well-formed.
        * n must be 0
        * the subdomain must not be independent of its domain

def check_initial_subdomain(cls, subdomain_rec):
        """
        Verify that a first-ever subdomain record is well-formed.
        * n must be 0
        * the subdomain must not be independent of its domain
        """
        if subdomain_rec.n != 0:
            return False
       
        if subdomain_rec.independent:
            return False

        return True