Important optimization for pan-allele models: pass network the 'name' of the allele rather than the sequence. Network uses a fixed non-trianable allele encoding that maps allele 'names' to sequences.

read_table was deprecated in version 0.24.0 and replaced with read_csv
(see
http://pandas.pydata.org/pandas-docs/stable//reference/api/pandas.read_table.html)

Fix bug that led to NaN mhcflurry_prediction_high and mhcflurry_prediction_low uncertainty estimates in some cases