diff --git a/src/local_search.py b/src/local_search.py
index 8cff412..3567ba6 100644
--- a/src/local_search.py
+++ b/src/local_search.py
@@ -7,11 +7,18 @@ def get_first_random_solution(m, data):
     return data.loc[random_indexes]
 
 
+def element_in_dataframe(solution, element):
+    duplicates = solution.query(
+        f"(source == {element.source} and destination == {element.destination}) or (source == {element.destination} and destination == {element.source})"
+    )
+    return not duplicates.empty
+
+
 def replace_worst_element(previous, data):
     solution = previous.copy()
     worst_index = solution["distance"].astype(float).idxmin()
     random_element = data.sample().squeeze()
-    while solution.isin(random_element.values.ravel()).any().any():
+    while element_in_dataframe(solution=solution, element=random_element):
         random_element = data.sample().squeeze()
     solution.loc[worst_index] = random_element
     return solution, worst_index