This is the story of how it took me about 3 hours to pull a key from a census data index into its own column.
The censusdata
library returns dataframes that have an index object:
In [1]: import censusdata
In [2]: df = censusdata.download('acs5', 2015, censusdata.censusgeo([('state', '23'), ('county', '005'), ('block group', '*')]), [('C02003_001E')]).head()
In [3]: df