return the percentage of the sequence which is equal to the passed nuc.

      :param nuc: the nucleotide to compute percentage composition for. There
                  is no check to make sure this is a valid nucleotide.
      :return: the percentage of the sequence that is <nuc>

def percentNuc(self, nuc):
    """
      return the percentage of the sequence which is equal to the passed nuc.

      :param nuc: the nucleotide to compute percentage composition for. There
                  is no check to make sure this is a valid nucleotide.
      :return: the percentage of the sequence that is <nuc>
    """
    count = reduce(lambda x, y: x + 1 if y == nuc else x, self.sequenceData, 0)
    return count / float(len(self.sequenceData))