def _generate_maf_long_df(self):
mafs = ThousandGenomes.mafs()
long_format_mafs = OrderedDict()
# population_level can be "population" or "superpopulation"
for population_level, dic in mafs.items():
names, frames = dic.keys(), dic.values()
merged_df = pd.concat(frames, axis=1, keys=names)
long_df = pd.melt(merged_df)
long_df.columns = ["panel", "population", "MAF"]
long_format_mafs[population_level] = long_df
return long_format_mafs
