source: Establish common way to pass arguments to subclasses of list/collections.UserList

[johnandersen777]

Update: We'll likely just make this into something that takes a config, there's not reason it has to take a list and not a config with a list in it.

Right now Sources is used as a list of BaseSource instances. The configuration of the sources works fine, however we haven't taken into account the configuration of the Sources class itself. We need to find a way to pass arguments to it. For reasons such as the following:

• #378: Add configuration parameter to Sources to toggle combination
  • Similar to #309: Decide if repo.merge should override existing feature data
• #380: Add configuration parameter to Sources to end at index or start at index

[sakshamarora1]

Hey, @pdxjohnny I'd like to work on this issue!

[johnandersen777]

@sakshamarora1 Hmm, I've been thinking on this and I'm not sure there's a great way to come at this right now. I think that https://github.com/intel/dffml/issues/326 would be the best place to start. Then we need to do #325. As you'll find when doing #326, there's a lot going on with the config stuff. It's what let's us specify the plugin name, and the config for that plugin. In the case of sources. It's still using the CLI style config stuff. Which is different and can't yet leverage the same way we allow for configuration of the class itself (sources in this case)

[sakshamarora1]

@pdxjohnny I'll dive into it then, thanks!