diff --git a/pandas_and_tidying_ex4.py b/pandas_and_tidying_ex4.py
index e69de29..407dfa9 100644
--- a/pandas_and_tidying_ex4.py
+++ b/pandas_and_tidying_ex4.py
@@ -0,0 +1,6 @@
+samp_mut = pd.merge(
+    sampleruns.reset_index(drop=True),
+    mutations.reset_index(drop=True),
+    left_on=['Strain ID','Population', 'Generation'],
+    right_on=['Strain ID','Population', 'Generation'],
+)
\ No newline at end of file