code: def get_srid(df):
      """Return srid from `df.crs`."""
      if df.crs is not None:
          return df.crs.to_epsg() or 0
      return 0
  
imports: import os.path
  from pandas import Series
  from geopandas import GeoDataFrame
  from geopandas.testing import assert_geoseries_equal, geom_almost_equals, geom_equals
label_desc: Use image node_id 2 for calling a global function with example usage: get_srid(df) and returns: int, unknown