Update simulation.py

simulation.py

@@ -142,7 +142,7 @@ class SequenceGenerator():
             r_motif = sequence[len(sequence)//2:]
             idx = 0
         seq = l_motif + "".join(np.random.choice(list("ATGC"), size=n)) + r_motif
-        new_mask = mask[:len(l_motif)]+[0]*n+mask[-len(r_motif):]
+        new_mask = mask[:len(l_motif)]+([0]*n)+mask[len(sequence)-len(r_motif):]
         return seq, new_mask, idx