code: def generate_tostr_testcases():
      """Flatten driver_converts_to_str to a list of (field_type, driver) tuples"""
      cases = []
      for field_type in _driver_converts_to_str:
          for driver in _driver_converts_to_str[field_type]:
              driver_supported = driver in supported_drivers
              driver_can_write = _driver_supports_mode(driver, "w")
              field_supported = _driver_supports_field(
                  driver, field_type
              )
              converts_to_str = (
                  _driver_converts_field_type_silently_to_str(
                      driver, field_type
                  )
              )
              if (
                  driver_supported
                  and driver_can_write
                  and converts_to_str
                  and field_supported
              ):
                  cases.append((field_type, driver))
      return cases
  
imports: import fiona
  from fiona._env import get_gdal_version_num, calc_gdal_version_num
  import pytest
  from fiona.errors import DriverSupportError
  from fiona.rfc3339 import parse_time, parse_datetime
  from .conftest import get_temp_filename
  from fiona.env import GDALVersion
  from fiona.model import Feature
  import datetime
  from fiona.drvsupport import supported_drivers, driver_mode_mingdal, _driver_converts_field_type_silently_to_str, _driver_supports_field, _driver_converts_to_str, _driver_supports_timezones, _driver_supports_milliseconds, _driver_supports_mode
  import pytz
  from pytz import timezone
label_desc: Use image node_id 19 for calling a global function with example usage: generate_tostr_testcases() and returns: cases