'DataFrameGroupBy' object has no attribute 'reset_index'

This error typically occurs when you try to call the `reset_index()` method on a `DataFrameGroupBy` object in pandas.

The `reset_index()` method is used to convert the index of a DataFrame into a column. However, `DataFrameGroupBy` objects are not DataFrames, but rather objects returned by the `groupby()` method that allow you to perform operations on subsets of a DataFrame.

To reset the index of a `DataFrameGroupBy` object, you can use the `agg()` method to apply an aggregation function to each group, and then call the `reset_index()` method on the resulting DataFrame. For example:

df.groupby('column').agg({'other_column': 'mean'}).reset_index()

This will group the DataFrame `df` by values in the 'column' column, calculate the mean of the 'other_column' for each group, and reset the index of the resulting DataFrame.