code: def process_crs(crs):
      """
      Parses cartopy CRS definitions defined in one of a few formats:
  
        1. EPSG codes:   Defined as string of the form "EPSG: {code}" or an integer
        2. proj.4 string: Defined as string of the form "{proj.4 string}"
        3. cartopy.crs.CRS instance
        4. None defaults to crs.PlateCaree
      """
      try:
          import cartopy.crs as ccrs
          import pyproj
      except ImportError:
          raise ImportError(
              "Geographic projection support requires pyproj and cartopy."
          ) from None
  
      if crs is None:
          return ccrs.PlateCarree()
      elif isinstance(crs, ccrs.CRS):
          return crs
  
      errors = []
      if isinstance(crs, str):
          try:
              return ccrs.epsg("".join([c for c in crs if c.isdigit()]))
          except Exception as e:
              errors.append(e)
      if isinstance(crs, int):
          try:
              return ccrs.epsg(crs)
          except Exception as e:
              crs = str(crs)
              errors.append(e)
      if isinstance(crs, (str, pyproj.Proj)):
          try:
              return proj_to_cartopy(crs)
          except Exception as e:
              errors.append(e)
  
      raise ValueError(
          "Projection must be defined as a EPSG code, proj4 string, cartopy CRS or pyproj.Proj."
      ) from Exception(*errors)
  
imports: import warnings
  import numpy
  import shapely
  import shapely.geometry
  from cartopy import crs
  from cartopy.io.img_tiles import GoogleTiles, QuadtreeTiles
  from holoviews.element import Tiles
  from packaging.version import Version
  from shapely.geometry import LinearRing, LineString, MultiLineString, MultiPoint, MultiPolygon, Point, Polygon, box
  from shapely.geometry.base import BaseMultipartGeometry
  from shapely.ops import transform
  from ._warnings import deprecated, warn
label_desc: Use image node_id 18 for calling a global function with example usage: process_crs(crs) and returns: ccrs, crs, ccrs, ccrs, proj_to_cartopy