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Code reviewMediumcr-g491
Subject Unnecessary allocationLevel Mid–Senior~18 minCommon in Code quality & review interviewsIndustries Software development

Question

Review this Python merge of per-shard counters.

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Separate real bugs from style. Rank issues by severity, point at the root cause rather than the symptom, and suggest a concrete fix — specific and kind.

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Code to reviewpython
def merge(shards):    totals = {}    for shard in shards:        for k, v in shard.items():            keys = list(totals.keys())     # snapshot keys each time            if k in keys:                totals[k] = totals[k] + v            else:                totals[k] = v    return totals
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