code: def parse_timestamp_msecs(ts: Optional[str]) -> Optional[int]:
      if ts is None:
          return ts
      dt = dateutil.parser.isoparse(ts)
      assert (
          dt.tzinfo is not None and dt.tzinfo.utcoffset(dt) is not None
      )
      return int((dt - _EPOCH) / _MS)
  
file_path: hail/hail/python/hailtop/utils/time.py
imports: import time
  from typing import Optional, overload, Union
  import datetime
  import dateutil.parser
  from ..humanizex import naturaldelta_msec
label_desc: Use image node_id 9 for calling a global function with example usage: parse_timestamp_msecs(ts) and returns: int, ts