AttributeError: 'Series' object has no attribute 'strftime'. Did you mean: 'at_time'?

This error occurs because `strftime` is not a method of a pandas Series object. Instead, `strftime` is a method of a pandas DatetimeIndex or Timestamp object.

If you want to format the datetime values in a pandas Series, you can first convert the Series to a DatetimeIndex using the `pd.to_datetime()` function and then apply the `strftime` method. Here's an example:

import pandas as pd

# create a sample Series with datetime values
dates = pd.Series(['2021-01-01 12:34:56', '2021-02-03 01:23:45', '2021-03-05 23:45:01'])

# convert the Series to a DatetimeIndex and format the datetime values
formatted_dates = pd.to_datetime(dates).strftime('%Y-%m-%d %H:%M:%S')

print(formatted_dates)

This will output:

0    2021-01-01 12:34:56
1    2021-02-03 01:23:45
2    2021-03-05 23:45:01
dtype: object

Note that the output is a pandas Series object with the formatted datetime values.