Multiple filtering doesn't seem to work

[XerXi]

Hello,
I am trying to import a database and its corresponding security group but I cannot seem to do that in 1 import command. Here's what I try:

1. This imports only the db:
   terraformer import aws --regions eu-central-1 --profile "" -r rds,sg --filter="Name=tags.Name;Value=dev" --filter=sg=sg-0899faec61d611123 --compact --path-pattern .

2. These import all db and all sgs:
   terraformer import aws --regions eu-central-1 --profile "" -r rds,sg --filter Type=rds;Name=tags.Name;Value=dev --filter Type=sg;Name=tags.Name;Value=dev.sg --compact --path-pattern .

terraformer import aws --regions eu-central-1 --profile "" -r rds,sg --filter="Type=rds;Name=tags.Name;Value=mpgdev" --filter="Type=security_group;Name=id;Value=sg-0899faec61d611123" --compact --path-pattern .

terraformer import aws --regions eu-central-1 --profile "" -r rds,sg --filter="Type=rds;Name=tags.Name;Value=mpgdev" --filter="Type=sg;Name=id;Value=sg-0899faec61d611123" --compact --path-pattern .

3. This imports all dbs and correct sg:
   terraformer import aws --regions eu-central-1 --profile "" -r rds,sg --filter="Type=rds;Name=tags.Name;Value=dev" --filter="Type=sg;Name=tags.Name;Value=dev.sg" --compact --path-pattern .

So it seems it takes only the last "filter" parameter.

As a whole, documentation is lacking on the filtering cases. It would nice if there are more examples, for each resource type even.