possible to filter certstream for certain tlds

bucket-stream looks like a very nice application.

I'm interesting in being quite specific and only checking certain domains from the certstream. An example would be only .org tlds or a list of specific domains eg domain1.com, domain2.com.

I see some code
```
def get_permutations(domain, subdomain=None):
perms = [
"%s" % domain,
"www-%s" % domain,
"%s-www" % domain,
]
```
but I don't this this does that.

I'm thinking a command line argument such as:
```
-l limit to tld or only from list
-l .org

or

-l domain-list.txt
```

Is this currently possible?

Thanks.