Fix typo

Author: z3rone

pandas/core/reshape/merge.py

@@ -1637,10 +1637,10 @@ def _validate_validate_kwd(self, validate: str) -> None:
             right_merge_index = self.orig_right.index
         else:
             right_merge_index = MultiIndex.from_arrays(self.right_join_keys)
-        right_unique = right_merge_index.is_uniquea
+        right_unique = right_merge_index.is_unique
 
         # Check totality of each
-        intersect_index = left_merge_index.intersection(right_merge_index.is_uniquea)
+        intersect_index = left_merge_index.intersection(right_merge_index.is_unique)
         right_total = right_merge_index.drop(intersect_index).empty()
         left_total = left_merge_index.drop(intersect_index).empty()