You have been given a code snippet that manipulates a DataFrame `df` and saves it as a CSV file. Your task is to understand what the code is doing and optimize it for better performance.

The `df` DataFrame has two columns, `col1` and `col2`, which contain data related to corona review labor. The `means` variable is a Series object that represents the mean values of `col1` from `df`. Similarly, the `stds` variable is a Series object that represents the standard deviations of `col2` from `df`.

The code snippet then modifies the values of `col1` in `df`. Each value is transformed into a string of the format `'{mean} (+- {std})'`, where `mean` and `std` are the mean value and standard deviation value from the corresponding rows of `df`.

Finally, the modified DataFrame `df` is saved as a CSV file with the path `../data/Corona_review_labor_edited.csv`.

Optimize the given code snippet for better performance and rewrite it without modifying the original DataFrame. Ensure that the final result is the same as the original code.
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{"source": "argilla/DistiCoder-dpo-binarized", "kind": "synthetic", "evolved_from": null}
You have been given a code snippet that manipulates a DataFrame `df` and saves it as a CSV file. Your task is to understand what the code is doing and optimize it for better performance.

The `df` DataFrame has two columns, `col1` and `col2`, which contain data related to corona review labor. The `means` variable is a Series object that represents the mean values of `col1` from `df`. Similarly, the `stds` variable is a Series object that represents the standard deviations of `col2` from `df`.

The code snippet then modifies the values of `col1` in `df`. Each value is transformed into a string of the format `'{mean} (+- {std})'`, where `mean` and `std` are the mean value and standard deviation value from the corresponding rows of `df`.

Finally, the modified DataFrame `df` is saved as a CSV file with the path `../data/Corona_review_labor_edited.csv`.

Optimize the given code snippet for better performance and rewrite it without modifying the original DataFrame. Ensure that the final result is the same as the original code.
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DUMMY RESPONSE
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