def doc_field_length(self, docnum, fieldid):
        raise NotImplementedError
Returns a list of the mapping[name] for each value in |names| that is in
dataset/ETHPy150Open dokipen/whoosh/src/whoosh/reading.py/IndexReader.doc_field_length--crossover with--dataset/ETHPy150Open adblockplus/gyp/pylib/gyp/generator/analyzer.py/_LookupTargets