Add shape property

Author: mkardas

sota_extractor2/data/table.py

@@ -146,6 +146,10 @@ def set_tags(self, tags):
                 # todo: change gold_tags to tags to avoid confusion
                 self.df.iloc[r,c].gold_tags = cell.strip()
 
+    @property
+    def shape(self):
+        return self.df.shape
+
     @property
     def matrix(self):
         return self.df.applymap(lambda x: x.value)