code: function(doc, def, labelTemplate) {
  	return Object.keys(doc)
  		.map(key => {
  			const field = doc[key]
  			const fieldDef = def[key]
  
  			if (!field || (!fieldDef && key != '_id')) {
  				return null
  			}
  
  			const name = key == '_id' ? 'id' : fieldDef.label
  			const template = labelTemplate || '%s'
  			const label = util.format(template, name)
  
  			if (typeof field == 'object' && !Array.isArray(field) && key != '_id') {
  				return getDocumentOutput(field, fieldDef.schemaType, label + ' (%s)')
  			}
  
  			return `${chalk.yellow(label)}: ${field}`
  
  		})
  		.filter(line => { return line !== null })
  		.join('\n')
  }
docs: Get the string representation of the document
  @param  {Object} doc
  @param  {Object} def
  @param  {String} [labelTemplate='%s']
  @return {String}