code: function(time, index, ticks, format) {
  		var me = this;
  		var adapter = me._adapter;
  		var options = me.options;
  		var formats = options.time.displayFormats;
  		var minorFormat = formats[me._unit];
  		var majorUnit = me._majorUnit;
  		var majorFormat = formats[majorUnit];
  		var majorTime = +adapter.startOf(time, majorUnit);
  		var majorTickOpts = options.ticks.major;
  		var major = majorTickOpts.enabled && majorUnit && majorFormat && time === majorTime;
  		var label = adapter.format(time, format ? format : major ? majorFormat : minorFormat);
  		var tickOpts = major ? majorTickOpts : options.ticks.minor;
  		var formatter = valueOrDefault$c(tickOpts.callback, tickOpts.userCallback);
  
  		return formatter ? formatter(label, index, ticks) : label;
  	}
docs: Function to format an individual tick mark
  @private