diff --git a/u7/hash_table.py b/u7/hash_table.py
index 5e3f762..a155614 100644
--- a/u7/hash_table.py
+++ b/u7/hash_table.py
@@ -91,4 +91,29 @@ class HashTable:
             idx = self.probe(key)
 
         self.slots[idx] = (key, value)
-        self._size += 1
\ No newline at end of file
+        self._size += 1
+    def __delitem__(self, key):
+        self._check_key(key)
+        idx = self.probe(key)
+        slot = self.slots[idx]
+
+        if slot is not self.empty and slot is not self.deleted and slot[0] == key:
+            self.slots[idx] = self.deleted
+            self._size -= 1
+        else:
+            raise KeyError(key)
+
+    def __contains__(self, key):
+        self._check_key(key)
+        idx = self.probe(key)
+        slot = self.slots[idx]
+        return slot is not self.empty and slot is not self.deleted and slot[0] == key
+
+    def __len__(self):
+        return self._size
+
+    def __iter__(self):
+        for slot in self.slots:
+            if slot is not self.empty and slot is not self.deleted:
+                yield slot[0]
+    
\ No newline at end of file