'Series' object has no attribute 'to_datetime'

This error occurs when you try to call the `to_datetime()` method on a pandas `Series` object, but the method does not exist for that object. This could happen if you have an older version of pandas installed, as the `to_datetime()` method was introduced in version 0.17.0.

To fix this error, you can either upgrade pandas to a newer version, or use a different method to convert the series to a datetime format. For example, you can use the `pd.to_datetime()` function to convert a series to a datetime format:

import pandas as pd

# create a series with some date strings
dates = pd.Series(['2020-01-01', '2020-01-02', '2020-01-03'])

# convert the series to a datetime format using pd.to_datetime()
dates = pd.to_datetime(dates)

This should convert the `dates` series to a datetime format without throwing the `'Series' object has no attribute 'to_datetime'` error.