MigrationProducer createMigratorFor(UsageInfo[] usages) {
    final Map<UsageInfo, Object> conversions = new HashMap<>();
    for (UsageInfo usage : usages) {
      final Object conversion = getConversion(usage.getElement());
      if (conversion != null) {
        conversions.put(usage, conversion);
      }
    }
    return new MigrationProducer(conversions);
  }
MigrationProducer createMigratorFor(UsageInfo[] usages)