Add --from option to vm.py, to generate Vm.sol from a local json file

scripts/vm.py

@@ -1,10 +1,12 @@
 #!/usr/bin/env python3
 
+import argparse
 import copy
 import json
 import re
 import subprocess
 from enum import Enum as PyEnum
+from pathlib import Path
 from typing import Callable
 from urllib import request
 
@@ -26,7 +28,16 @@
 
 
 def main():
-    json_str = request.urlopen(CHEATCODES_JSON_URL).read().decode("utf-8")
+    parser = argparse.ArgumentParser(
+            description="This script generates the Vm interface based on the cheatcodes json generated in Foundry")
+    parser.add_argument(
+            "--from",
+            metavar="PATH",
+            dest="path",
+            required=False,
+            help="path to a json file containing the Vm interface, as generated by Foundry")
+    args = parser.parse_args()
+    json_str = Path(args.path).read_text() if args.path is not None else request.urlopen(CHEATCODES_JSON_URL).read().decode("utf-8")
     contract = Cheatcodes.from_json(json_str)
 
     ccs = contract.cheatcodes