1 files changed, 13 insertions, 0 deletions
diff --git a/taskflow/utils/iter_utils.py b/taskflow/utils/iter_utils.py
index 68810e8..a96e9cf 100644
--- a/taskflow/utils/iter_utils.py
+++ b/taskflow/utils/iter_utils.py
@@ -16,12 +16,25 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import itertools
+
 
 def count(it):
     """Returns how many values in the iterator (depletes the iterator)."""
     return sum(1 for _value in it)
 
 
+def unique_seen(it, *its):
+    """Yields unique values from iterator(s) (and retains order)."""
+    seen = set()
+    for value in itertools.chain(it, *its):
+        if value in seen:
+            continue
+        else:
+            yield value
+            seen.add(value)
+
+
 def find_first_match(it, matcher, not_found_value=None):
     """Searches iterator for first value that matcher callback returns true."""
     for value in it: