docs: def set_governors(self, gov, rg=None):
          '''
          Set governors
  
          gov: str name of the governor
          rg: list of range of cores
          '''
          to_change = self.__get_ranges("online")
          if type(rg) == int:
              rg= [rg]
          if rg: to_change= set(rg) & set(self.__get_ranges("online"))
          for cpu in to_change:
              fpath = path.join("cpu%i"%cpu,"cpufreq","scaling_governor")
              self.__write_cpu_file(fpath, gov.encode())