code: private void read_env() {
          String env;
          try {
              if ((env = System.getProperty("TANGO_HOST")) == null) {
  		if ((env = System.getenv("TANGO_HOST")) == null) {
  		    Except.throw_connection_failed("TangoApi_TANGO_HOST_NOT_SET",
  			    "Property \"TANGO_HOST\" not exported", "TangoDs.Util.read_env()");
  		}
  	    }
  
  	    assert env != null;
  	    if (env.indexOf(":") < 0) {
  		Except.throw_connection_failed("TangoApi_TANGO_HOST_NOT_SET",
  			"Unknown \"TANGO_HOST\" property " + env, "TangoDs.Util.read_env()");
  	    }
  	    final String[] array = ApiUtil.parseTangoHost(env);
  	    db_host = array[0];
  	} catch (final DevFailed e) {
  	    Except.print_exception(e);
  	    System.exit(-1);
  	}
      }
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