[pre-commit.ci] auto fixes from pre-commit.com hooks

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Author: pre-commit-ci[bot]

dynamic_programming/arithmetic_slices.py

@@ -53,7 +53,7 @@ def numberofarithmeticslices(self, nums):
         to check if they form an arithmetic pattern.
 
 <<<<<<< HEAD
-        So at each step, 
+        So at each step,
         we are looking at a triplet ending at index `i`.
 =======
         So at each step,