code: def checkAlphabet(self, count=10):
          
          if six.PY3:
              readLetters = super().checkAlphabet(count)
          else:
              readLetters = Read.checkAlphabet(self, count)
          if len(self) > 10 and readLetters.issubset(set('ACGT')):
              raise ValueError('It looks like a DNA sequence has been passed to '
                               'AARead().')
          return readLetters
docs: A function which checks if an AA read really contains amino acids. This
          additional testing is needed, because the letters in the DNA alphabet
          are also in the AA alphabet.
  
          @param count: An C{int}, indicating how many bases or amino acids at
              the start of the sequence should be considered. If C{None}, all
              bases are checked.
          @return: C{True} if the alphabet characters in the first C{count}
              positions of sequence is a subset of the allowed alphabet for this
              read class, or if the read class has a C{None} alphabet.
          @raise ValueError: If a DNA sequence has been passed to AARead().