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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def process_all(self, texts:Collection[str]) -> List[List[str]]:
        "Process a list of `texts`."
        if self.n_cpus <= 1: return self._process_all_1(texts)
        with ProcessPoolExecutor(self.n_cpus) as e:
            return sum(e.map(self._process_all_1, partition_by_cores(texts, self.n_cpus)), [])