old_contents: var _ = require('underscore');
  var debug = require('debug')('grainstore:carto-renderer-child');
  var MMLBuilder = require('../mml_builder');
  
  process.on('message', function(input) {
      debug('Child got Mapnik MML');
  
      try {
          var mmlBuilder = new MMLBuilder(input.ctx.params, input.ctx.options);
  
          _.extend(mmlBuilder, input.ctx);
  
          mmlBuilder.toXML(function (err, xml) {
              if (err) {
                  return process.send({ err: err.message });
              }
  
              process.send({ xml: xml });
          });
      } catch (err) {
          return process.send({err: err.message});
      }
  });
  
new_contents: var _ = require('underscore');
  var debug = require('debug')('grainstore:carto-renderer-child');
  var MMLBuilder = require('../mml_builder');
  
  process.on('message', function(input) {
      debug('Child got Mapnik MML');
  
      try {
          var mmlBuilder = new MMLBuilder(input.ctx.params, input.ctx.options);
  
          _.extend(mmlBuilder, input.ctx);
  
          mmlBuilder.toXML(function (err, xml) {
              if (err) {
                  return process.send({ err: err.message });
              }
  
              process.send({ xml: xml });
          });
      } catch (err) {
          return process.send({ err: err.message });
      }
  });
  
subject: Use consistent spacing