create_from_reference.py

from anki.collection import *
from anki.import_export_pb2 import *
import os

# Step 1: create a temporary collection
try:
    # delete if exists already
    os.remove("temporary.anki2")
except OSError:
  pass
# then start fresh
col = Collection("temporary.anki2")

# Step 2: import the template APKG with the note type, so that you can add data
col.import_anki_package(ImportAnkiPackageRequest(
    # this is what you exported from Anki
    package_path="reference.apkg",
    # the options don't matter that much in our case
    # since the collection we import into is empty anyway
    options=ImportAnkiPackageOptions(
        merge_notetypes=True,
        update_notes=ImportAnkiPackageUpdateCondition.IMPORT_ANKI_PACKAGE_UPDATE_CONDITION_ALWAYS,
        update_notetypes=ImportAnkiPackageUpdateCondition.IMPORT_ANKI_PACKAGE_UPDATE_CONDITION_NEVER,
        with_scheduling=False,
        with_deck_configs=False,
    )
))

## Step 3: find the note type id we want to modify, and get the dictionary
note_type_id_for_template_replacement = None
for note_type in col.models.all_names_and_ids():
  if note_type.name == "Japanese vocabulary":
    note_type_id_for_template_replacement = note_type.id
if note_type_id_for_template_replacement is None:
  raise Exception("Note type to modify templates of not found")

## Step 4: get the current note type dict
note_type = col.models.get(note_type_id_for_template_replacement)

## Step 5: set your one template (or more, in the same way)
with open("dist/front.html", "r") as front_file:
  with open("dist/back.html") as back_file:
    front_html = front_file.read()
    back_html = back_file.read()
note_type["tmpls"][0]["qfmt"] = front_html
note_type["tmpls"][0]["afmt"] = back_html

## Step 5: write your changes back to the Anki collection
col.models.update_dict(note_type)

# Step 6: Done, now we just need to export an APKG
col.export_anki_package(
    # anki fails if this is just an apkg filename without a dir,
    # with ./ it's fine
    out_path="./cool_new_template.apkg",
    options=ExportAnkiPackageOptions(
        with_deck_configs=False,
        with_media=True,
        with_scheduling=False,
        legacy=True,
    ),
    limit=None)