value.
    :param writable: if true, a writable check is performed.
    :param readable: if true, a readable check is performed.
    :param resolve_path: if this is true, then the path is fully resolved
                         before the value is passed onwards.  This means
                         that it's absolute and symlinks are resolved.  It
                         will not expand a tilde-prefix, as this is
                         supposed to be done by the shell only.
    :param allow_dash: If this is set to `True`, a single dash to indicate
                       standard streams is permitted.
    :param path_type: optionally a string type that should be used to
                      represent the path.  The default is `None` which
                      means the return value will be either bytes or
                      unicode depending on what makes most sense given the
                      input data Click deals with.
    FTNc