docs: def query_server(self,outfile,age,metallicity):
          """ Server query for the isochrone file.
  
          Parameters:
          -----------
          outfile     : name of output isochrone file
          age         : isochrone age
          metallicity : isochrone metallicity
          
          Returns:
          --------
          outfile     : name of output isochrone file
          """
          params = copy.deepcopy(self.download_defaults)
  
          epsilon = 1e-4
          lage = np.log10(age*1e9)
          lage_min,lage_max = params['isoc_lage0'],params['isoc_lage1']
          if not (lage_min-epsilon < lage <lage_max+epsilon):
              msg = 'Age outside of valid range: %g [%g < log(age) < %g]'%(lage,lage_min,lage_max)
              raise RuntimeError(msg)
  
          z_min,z_max = params['isoc_z0'],params['isoc_z1']
          if not (z_min <= metallicity <= z_max):
              msg = 'Metallicity outside of valid range: %g [%g < z < %g]'%(metallicity,z_min,z_max)
              raise RuntimeError(msg)
          
          params['photsys_file'] = photsys_dict[self.survey]
          params['isoc_age']     = age * 1e9
          params['isoc_zeta']    = metallicity
  
          server = self.download_url
          url = server + '/cgi-bin/cmd_%s'%params['cmd_version']
          # First check that the server is alive
          logger.debug("Accessing %s..."%url)
          urlopen(url,timeout=2)
  
          q = urlencode(params).encode('utf-8')
          logger.debug(url+'?'+q)
          c = str(urlopen(url, q).read())
          aa = re.compile('output\d+')
          fname = aa.findall(c)
          
          if len(fname) == 0:
              msg = "Output filename not found"
              raise RuntimeError(msg)
  
          out = '{0}/tmp/{1}.dat'.format(server, fname[0])
          
          cmd = 'wget --progress dot:binary %s -O %s'%(out,outfile)
          logger.debug(cmd)
          stdout = subprocess.check_output(cmd,shell=True,stderr=subprocess.STDOUT)
          logger.debug(stdout)
  
          return outfile