As far as I see this here supports a special syntax for template parsing and has some features to add and remove text/document content parts.
Now
They also support a special syntax, see the example they provide here:

From the first look, their syntax (supporting loops etc.) even looks more elaborate. They just seem to use XML for inputting data, while you use JSON or a dictionary.
So what is the advantage of your library here?
Maybe you want to document that in a Readme.
As far as I see this here supports a special syntax for template parsing and has some features to add and remove text/document content parts.
Now

They also support a special syntax, see the example they provide here:
From the first look, their syntax (supporting loops etc.) even looks more elaborate. They just seem to use XML for inputting data, while you use JSON or a dictionary.
So what is the advantage of your library here?
Maybe you want to document that in a Readme.