def iso8601_from_timestamp(timestamp):
    return isotime(datetime.datetime.utcfromtimestamp(timestamp))
private method to collect metrics for a single variant (var) in a VCF file.
dataset/ETHPy150Open openstack/python-monascaclient/monascaclient/openstack/common/timeutils.py/iso8601_from_timestamp--crossover with--dataset/ETHPy150Open arq5x/gemini/gemini/gemini_load_chunk.py/GeminiLoader._prepare_variation