CLICommonval define_oasis_fn :
(OASISTypes.host_filename -> 'a) CLISubCommand.run_t ->
'a CLISubCommand.run_tAdd arguments to define where is located '_oasis'.
val parse_oasis_fn :
(OASISTypes.host_filename -> OASISTypes.package -> 'a) CLISubCommand.run_t ->
'a CLISubCommand.run_tLocate '_oasis' and parse it.