def keys(self):
        return list(self)
find closest occurance of site in self.seq
dataset/ETHPy150Open PythonCharmers/python-future/docs/3rd-party-py3k-compat-code/pandas_py3k.py/_OrderedDict.keys--crossover with--dataset/ETHPy150Open adamewing/bamsurgeon/bamsurgeon/mutableseq.py/MutableSeq.find_site