val initialise :
?ctx:Client.ctx->endpoint:string ->?email:string ->X509.Private_key.t ->(Letsencrypt.Client.t, [> `HTTP of Client.error| `Msg of string ])Stdlib.resultLwt.t
val sign_certificate :
?ctx:Client.ctx->solver->Letsencrypt.Client.t->(int ->unit Lwt.t)->X509.Signing_request.t ->(X509.Certificate.t list, [> `HTTP of Client.error| `Msg of string ])Stdlib.resultLwt.t