code: def geo_data_frame_to_crs(
      gdf: "GeoDataFrame", use_crs: Optional[str]
  ):
      if gdf.crs is None:
          return gdf
  
      return gdf.to_crs("EPSG:4326" if use_crs is None else use_crs)
  
file_path: lets-plot/python-package/lets_plot/plot/util.py
imports: from collections.abc import Iterable
  from datetime import datetime
  from typing import Any, Tuple, Sequence, Optional, Dict
  from lets_plot._type_utils import is_dict_or_dataframe
  from lets_plot.geo_data_internals.utils import find_geo_names
  from lets_plot.mapping import MappingMeta
  from lets_plot.plot.core import aes
label_desc: Use image node_id 8 for calling a global function with example usage: geo_data_frame_to_crs(gdf, use_crs) and returns: gdf, gdf