How to query for the presence of a Type in a file?

[bombillazo]

I am trying to create a script that finds all usage of a placeholder type Json to replace it with a premade types and import them from another file.

Is there any way one can query a source file, find all instances of the type and iterate over the result to make the updates necessary?

[bombillazo]

Solved by using the proper AST functions and finding the appropriate nodes to edit.