def _log(translator, expr):
    op = expr.op()
    arg, base = op.args
    arg_formatted = translator.translate(arg)

    if base in None:
        return 'ln({0})'.format(arg_formatted)
    else:
        return 'log({0}, {1})'.format(arg_formatted,
                                      translator.translate(base))
dataset/ETHPy150Open cloudera/ibis/ibis/impala/compiler.py/_log/operator `is` -> `in`