code: function renderPatternPartial(patternId, drizzleData, Handlebars) {
    const patternObj = deepPattern(patternId, drizzleData.patterns);
    const localContext = patternContext(patternObj, drizzleData);
    let template = Handlebars.partials[patternId];
    if (typeof template !== 'undefined') {
      if (typeof template !== 'function') {
        template = Handlebars.compile(template);
      }
      // Render and return
      return template(localContext);
    }
    DrizzleError.error(
      new DrizzleError(
        `Partial for pattern ${patternId} not found`,
        DrizzleError.LEVELS.ERROR
      ),
      drizzleData.options.debug
    );
  }
docs: Retrieve correct pattern object data, find the right partial and
  compile with correct local context.
  TODO: How do we test this?