def backtranslate(faa, fna):
newfna = ExtendedAlignment(faa.fragments)
for k, s in fna.items():
if k in faa.keys():
aa = faa[k].upper()
cd = []
i = 0
for r in aa:
cds = s[i:i + 3]
if r == '-':
cd.append('---')
else:
if is_compatible(cds, r):
cd.append(cds)
i += 3
else:
if i == 0 and (cds == 'GTG' or cds == 'TTG'):
cd.append(cds)
i += 3
else:
raise ValueError('%s at position %d of %s '
'does not translate to %s' %
(cds, i, k, r))
newfna[k] = ''.join(cd)
else:
continue
col_lab = faa.col_labels
for i in col_lab:
newfna._col_labels = newfna._col_labels + [i, i, i]
return newfna
