code: function dummyDataWithAllTags(...tagList){
      if(!is.all.string(tagList)) throw new TypeError('all specified tags must be strings');
      const ans = [];
      for(const td of Object.values(muQUnitUtil.allDummyData)){
          for(const dd of Object.values(td)){
              // make sure every tag is present
              let allPresent = true;
              for(const t of tagList){
                  if(!dd.hasTag(t)){
                      allPresent = false;
                      break;
                  }
              }
              if(allPresent) ans.push(dd);
          }
      }
      return ans;
  }
docs: Returns the dummy data matching **all** of the given tags.
  
  @param {...string} tagList
  @return {DummyData[]}
  @throws {TypeError}