Update fractional_cover_problem.py

Author: debnath003

Diff for: greedy_methods/fractional_cover_problem.py

@@ -27,6 +27,8 @@ def __eq__(self, other: "Item") -> bool:
         >>> item1 == item3
         False
         """
+        if not isinstance(other, Item):
+            return NotImplemented
         return self.weight == other.weight and self.value == other.value