def normalize_letters(one_letter_code):
 if (one_letter_code == '.'):
  return 'X'
 else:
  return one_letter_code.upper()

def normalize_letters ( one_letter_code ) : if ( one_letter_code == '.' ) : return 'X' else : return one_letter_code . upper ( )
convert raf one-letter amino acid codes into iupac standard codes .