module 'pandas' has no attribute 'rolling_min'

The reason you are getting this error is because the `rolling_min` function was removed from Pandas version 0.18.0 onwards. Instead, you can use the `rolling` function with the `min` method to achieve the same result. Here is an example:

import pandas as pd

# create a sample dataframe
df = pd.DataFrame({'A': [1, 2, 3, 4, 5]})

# calculate rolling minimum with window size 2
rolling_min = df['A'].rolling(window=2).min()

# print the result
print(rolling_min)

This will output:

0    NaN
1    1.0
2    2.0
3    3.0
4    4.0
Name: A, dtype: float64

As you can see, the `rolling` function with the `min` method calculates the rolling minimum over a specified window size.