4. The conveyance or grant shall include such provisions (if any) as the landlord may require to secure that a tenant is bound by, or to indemnify the landlord against breaches of, restrictive covenants (that is to say, covenants or agreements restrictive of the use of any land or premises) which affect the dwelling-house otherwise than by virtue of the tenancy or an agreement collateral to it and are enforceable for the benefit of other property.