2 files changed, 28 insertions, 8 deletions
diff --git a/Homeworks.md b/Homeworks.md
index 79eb7b2..3a20327 100644
--- a/Homeworks.md
+++ b/Homeworks.md
@@ -10,7 +10,7 @@ $ make docker-check
 
 - [X] TestFiniteSetRepresentation
 - [X] TestFiniteSetProperties
-- [X] TestFiniteMakeSetProduct
+- [ ] TestFiniteMakeSetProduct
 - [ ] TestFiniteMapRepresentation
 - [ ] TestFiniteMapOperations
 - [ ] TestFiniteSetRepresentation
diff --git a/src/act4e_solutions/sets_representation.py b/src/act4e_solutions/sets_representation.py
index 64d958a..32931da 100644
--- a/src/act4e_solutions/sets_representation.py
+++ b/src/act4e_solutions/sets_representation.py
@@ -1,6 +1,7 @@
 from typing import Any, Collection, Iterator, List, TypeVar, cast
 
 import act4e_interfaces as I
+from .sets_product import MyFiniteSetProduct
 
 E = TypeVar("E")
 
@@ -18,7 +19,7 @@ class MyFiniteSet(I.FiniteSet[E]):
     def elements(self) -> Iterator[E]:
         return iter(self._elements)
 
-    def save(self, h: I.IOHelper, x: E) -> I.ConcreteRepr:
+    def save(self, h: I.IOHelper, x: E) -> List[E]:
         return cast(I.ConcreteRepr, x)
 
     def load(self, h: I.IOHelper, o: I.ConcreteRepr):
@@ -30,14 +31,33 @@ class SolFiniteSetRepresentation(I.FiniteSetRepresentation):
         if not isinstance(data, dict):
             raise I.InvalidFormat()
 
-        if not "elements" in data:
-            raise I.InvalidFormat()
+        if "elements" in data:
+            if not isinstance(data["elements"], list):
+                raise I.InvalidFormat()
 
-        if not isinstance(data["elements"], list):
-            raise I.InvalidFormat()
+            elements = data["elements"]
+            return MyFiniteSet(elements)
+
+        elif "product" in data:
+            if not isinstance(data["product"], list):
+                raise I.InvalidFormat()
+
+            components = []
+            for comp in data["product"]:
+                if not isinstance(comp, dict):
+                    raise I.InvalidFormat()
 
-        elements = data["elements"]
-        return MyFiniteSet(elements)
+                if not "elements" in comp:
+                    raise I.InvalidFormat()
+
+                if not isinstance(comp["elements"], list):
+                    raise I.InvalidFormat()
+
+                components.append(MyFiniteSet(comp["elements"]))
+                return MyFiniteSetProduct(components)
+
+        else:
+            raise I.InvalidFormat()
 
     def save(self, h: I.IOHelper, f: I.FiniteSet[Any]) -> I.FiniteSet_desc:
         all_elements = [f.save(h, e) for e in f.elements()]