code: def parse_datetime_format_str(format_str):
      """Parse datetime `format_str` to interpret the `data`."""
  
      # timestamp 'ts{unit}:tz'
      timestamp_meta = re.match(r"ts([smun]):(.*)", format_str)
      if timestamp_meta:
          unit, tz = timestamp_meta.group(1), timestamp_meta.group(2)
          if unit != "s":
              # the format string describes only a first letter of the unit, so
              # add one extra letter to convert the unit to numpy-style:
              # 'm' -> 'ms', 'u' -> 'us', 'n' -> 'ns'
              unit += "s"
  
          return unit, tz
  
      raise NotImplementedError(
          f"DateTime kind is not supported: {format_str}"
      )
  
file_path: vegafusion/python/vegafusion/vegafusion/datasource/dfi_datasource.py
imports: from typing import Iterable
  import re
  import pyarrow
  from typing import Any, Dict
  from ._dfi_types import DtypeKind, DataFrame
  from .datasource import Datasource
label_desc: Use image node_id 1 for calling a global function with example usage: parse_datetime_format_str(format_str) and returns: unit,  tz