help understand this:
Codegen to automate staging table generation. It’s very good practice to learn to write staging models by hand, they’re straightforward and numerous, so they can be an excellent way to absorb the dbt style of writing SQL. Also, we’ll invariably find ourselves needing to add special elements to specific models at times — for instance, in one of the situations above that require base models — so it’s helpful to deeply understand how they work. Once that understanding is established though, because staging models are built largely following the same rote patterns and need to be built 1-to-1 for each source table in a source system, it’s preferable to start automating their creation. For this, we have the codegen package. This will let you automatically generate all the source YAML and staging model boilerplate to speed up this step, and we recommend using it in every project.