> head -n 4 crm.csv
id,active,tier
1,Y,silver
2,Y,bronze
3,N,gold
> head -n 4 warehouse.csv
id,active,tier
1,true,silver
2,true,bronze
3,false,gold
> veridelta crosswalk -c crosswalk.yaml
Loading configuration from crosswalk.yaml...
Lining up source and target values...
active: 2 new value_map entries
  'Y' -> 'true': 10 of 10 rows (100.0%)
  'N' -> 'false': 5 of 5 rows (100.0%)
rules:
- column_names:
  - active
  value_map:
    Y: 'true'
    N: 'false'
