In that step, we extract the summarized values and effectively convert that series to a dataframe. Unfortunately, there are edges cases where an empty result is returned. When empty, the group by returns an empty dataframe. This causes a value error on the columns reset. Let's handle this more explicitly by extracting series value as expected.
In wait time generation, we expect a series returned during the following summarize operation: https://github.com/kuanb/peartree/blob/b1e8677c8af89e5f37c203116706cc4fe9365603/peartree/summarizer.py#L139-L142
In that step, we extract the summarized values and effectively convert that series to a dataframe. Unfortunately, there are edges cases where an empty result is returned. When empty, the group by returns an empty dataframe. This causes a value error on the columns reset. Let's handle this more explicitly by extracting series value as expected.