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

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Author: pre-commit-ci[bot]

backtracking/generate_parentheses_iterative.py

@@ -2,6 +2,8 @@
 Generate Parentheses using Iterative Backtracking.
 https://leetcode.com/problems/generate-parentheses/
 """
+
+
 def generate_parentheses_iterative(length: int) -> list:
     """
     Generate all valid combinations of parentheses (Iterative Approach).