This function is deprecated as of choroplethr version 3.0.0. Please use ?state_choropleth_acs,
?county_choropleth_acs, ?zip_choropleth_acs. The last version of choroplethr
in which this function worked was version 2.1.1, which can be downloaded from CRAN
here: http://cran.r-project.org/web/packages/choroplethr/index.html