Add mapRemoveAll to basic spells

examples/spells/basicSpells.qnt

@@ -123,4 +123,21 @@ module basicSpells {
     assert(Map(3 -> 4, 7 -> 8) == Map(3 -> 4, 5 -> 6, 7 -> 8).mapRemove(5)),
     assert(Map() == Map().mapRemove(3)),
   }
-}
+
+  /// Removes a set of map entry.
+  ///
+  /// - @param __map a map to remove an entry from
+  /// - @param __keys a set of keys to remove from the map
+  /// - @returns a new map that contains all entries of __map
+  ///          that do not have a key in __keys
+  pure def mapRemoveAll(__map: a -> b, __keys: Set[a]): a -> b = {
+      __map.keys().exclude(__keys).mapBy(__k => __map.get(__k))
+  }
+
+  run mapRemoveAllTest =
+      val m = Map(3 -> 4, 5 -> 6, 7 -> 8)
+      all {
+          assert(m.mapRemoveAll(Set(5, 7)) == Map(3 -> 4)),
+          assert(m.mapRemoveAll(Set(5, 99999)) == Map(3 -> 4, 7 -> 8)),
+      }
+}