materializers.py

from hamilton import driver, base
from hamilton.io.materialization import to

json_saver = to.json(
    id="saved_json_object",  # name given to the saver
    dependencies=["a", "b", "c"],  # node returning the model
    combine=base.DictResult() # put a, b, c together as a dict
)

dr = (
    driver.Builder()
    .with_modules(my_module)
    .with_materializers(json_saver)
    .build()
)

dr.execute(["saved_json_object"], inputs={"external_input" : 10})