def map(self, fields):
    results = []

    start_bin = self.compute_start_bin(fields)
    if self.is_variant(fields):
      end_bin = start_bin
    else:
      end_bin = self.compute_end_bin(fields)

    for current_bin in range(start_bin, end_bin+1):
      key = (fields['reference_name'], str(current_bin)) % '%s:%s'
      results.append(Pair(key, fields))

    return results
dataset/ETHPy150Open googlegenomics/codelabs/Python/PlatinumGenomes-variant-transformation/gvcf_expander.py/GvcfExpander.map/swapped operands of `%`