In this post I am refering to 
this page in the documentation.
It states:
using CMS.SiteProvider;
 
using CMS.GlobalHelper;
 
 
 
private void CachingExample()
 
{
 
  DataSet data = null;
 
 
 
  // Cache the data for 10 minutes with key "mykey"
 
  using (CachedSection<DataSet> cs = new CachedSection<DataSet>(ref data, 10, true, null, "mykey"))
 
   {
 
      if (cs.LoadData)
 
       {
 
           data = UserInfoProvider.GetAllUsers(); // Get data from database
 
           cs.CacheDependency = CacheHelper.GetCacheDependency("somekey"); // Cache dependency
 
           cs.Data = data; // Save data to cache
 
       }
 
   }
 
}
Why are there two distincts key used in this code snippet? 
mykey and 
somekey are used. Is there something I am missing here?
What is the relation between the newly added cached section and the cache dependency?
The code works just fine, I am just wondering why two different keys are used in this case.
Any tip would be very appreciated.
Regards,