code: public static AssignedAddOnFetcher fetcher(final String pathAccountSid, 
                                                 final String pathResourceSid, 
                                                 final String pathSid) {
          return new AssignedAddOnFetcher(pathAccountSid, pathResourceSid, pathSid);
      }
docs: Create a AssignedAddOnFetcher to execute fetch.
  
  @param pathAccountSid The SID of the Account that created the resource to
  fetch
  @param pathResourceSid The SID of the Phone Number that installed this Add-on
  @param pathSid The unique string that identifies the resource
  @return AssignedAddOnFetcher capable of executing the fetch