val set_user_name : 
  t ->
  repo_root:Volgo__.Repo_root.t ->
  user_name:Volgo__.User_name.t ->
  (unit, Pplumbing_err.Err.t) Stdlib.Result.tval set_user_email : 
  t ->
  repo_root:Volgo__.Repo_root.t ->
  user_email:Volgo__.User_email.t ->
  (unit, Pplumbing_err.Err.t) Stdlib.Result.t