Fix bug because of small API change

edpop_explorer/reader.py

@@ -92,7 +92,7 @@ def adjust_start_record(self, start_number: int) -> None:
         This functionality may be ignored by readers that can only load 
         all records at once; generally these are readers that return lazy 
         records."""
-        if self.records is not None:
+        if self.number_of_results is not None:
             raise ReaderError(
                 "adjust_start_record should not be called after fetching."
             )