def METHOD_NAME(self):
    """Determine CPLEX bin subdirectory."""
    # avoid failing miserably under --module-only --force
    if os.path.exists(self.installdir) and os.listdir(self.installdir):
        bin_glob = 'cplex/bin/x86-64*'
        change_dir(self.installdir)
        bins = glob.glob(bin_glob)
        if len(bins) == 1:
            self.bindir = bins[0]
        elif len(bins) > 1:
            raise EasyBuildError("More than one possible path for bin found: %s", bins)
        else:
            raise EasyBuildError("No bins found using %s in %s", bin_glob, self.installdir)
    else:
        self.bindir = 'UNKNOWN'