NameError: name 'resample' is not defined

The error message suggests that you are trying to use a variable or function called `resample`, but it has not been defined in your code.

`resample` is a function provided by the `pandas` library that is used for resampling time-series data. To use the `resample` function, you need to first import the `pandas` library using the following code:

import pandas as pd

Then, you can use the `resample` function on a pandas DataFrame object like this:

df_resampled = df.resample('D').sum()

This will resample the data in `df` at a daily frequency and calculate the sum of the values for each day.

Make sure that you have imported the `pandas` library before using any of its functions.