{
  "name": "edit_existing_file",
  "arguments": {
    "filepath": "test.py",
    "changes": """
def existing_function():
    pass

def sliding_window(arr, k):
    # Initialize variables
    max_sum = float('-inf')
    current_sum = 0
    
    # Iterate over the array
    for i in range(len(arr)):
        current_sum += arr[i]
        
        if i >= k:
            current_sum -= arr[i - k]
        
        if i >= k - 1:
            max_sum = max(max_sum, current_sum)
    
    return max_sum

# Example usage
if __name__ == "__main__":
    arr = [1, 3, -2, 5, -6]
    k = 3
    print(sliding_window(arr, k))  # Output: 6
"""
  }
}