Fix sorting package imports

Author: shorodilov

src/sorting/__init__.py

@@ -61,21 +61,13 @@
     "heap_sort",
     "insertion_sort",
     "merge_sort",
+    "merge_lists",
     "quick_sort",
     "radix_sort",
     "selection_sort",
     "shell_sort"
 ]
 
-from sorting.func import (
-    bubble_sort,
-    bucket_sort,
-    counting_sort,
-    heap_sort,
-    insertion_sort,
-    merge_sort,
-    quick_sort,
-    radix_sort,
-    selection_sort,
-    shell_sort,
-)
+from sorting.func import (bubble_sort, bucket_sort, counting_sort, heap_sort,
+                          insertion_sort, merge_lists, merge_sort, quick_sort,
+                          radix_sort, selection_sort, shell_sort)