Databook.add_sheet accepts Dataset subclasses

2 files changed, 16 insertions, 1 deletions

diff --git a/tablib/core.py b/tablib/core.py
index 46146db..c52671e 100644
--- a/tablib/core.py
+++ b/tablib/core.py
@@ -955,7 +955,7 @@ class Databook(object):
 
     def add_sheet(self, dataset):
         """Adds given :class:`Dataset` to the :class:`Databook`."""
-        if type(dataset) is Dataset:
+        if isinstance(dataset, Dataset):
             self._datasets.append(dataset)
         else:
             raise InvalidDatasetType
diff --git a/test_tablib.py b/test_tablib.py
index 02a1eb3..fbb6eab 100755
--- a/test_tablib.py
+++ b/test_tablib.py
@@ -669,5 +669,20 @@ Old       |Man       |100500
         )
 
 
+    def test_databook_add_sheet_accepts_dataset_subclasses(self):
+        class DatasetSubclass(tablib.Dataset):
+            pass
+
+        # just checking if subclass of tablib.Dataset can be added to Databook
+        dataset = DatasetSubclass()
+        dataset.append(self.john)
+        dataset.append(self.tom)
+
+        try:
+            book.add_sheet(dataset)
+        except tablib.InvalidDatasetType:
+            self.fail("Subclass of tablib.Dataset should be accepted by Databook.add_sheet")
+
+
 if __name__ == '__main__':
     unittest.main()