code: def calculate_area_extent(area_dict):
      """Calculate the area extent seen by a geostationary satellite.
  
      Args:
          area_dict: A dictionary containing the required parameters
              center_point: Center point for the projection
              north: Northmost row number
              east: Eastmost column number
              west: Westmost column number
              south: Southmost row number
              column_step: Pixel resolution in meters in east-west direction
              line_step: Pixel resolution in meters in south-north direction
              [column_offset: Column offset, defaults to 0 if not given]
              [line_offset: Line offset, defaults to 0 if not given]
  
      Returns:
          tuple: An area extent for the scene defined by the lower left and
                 upper right corners
  
      # For Earth model 2 and full disk VISIR, (center_point - west - 0.5 + we_offset) must be -1856.5 .
      # See MSG Level 1.5 Image Data Format Description Figure 7 - Alignment and numbering of the non-HRV pixels.
      """
      center_point = area_dict["center_point"]
      east = area_dict["east"]
      west = area_dict["west"]
      south = area_dict["south"]
      north = area_dict["north"]
      column_step = area_dict["column_step"]
      line_step = area_dict["line_step"]
      column_offset = area_dict.get("column_offset", 0)
      line_offset = area_dict.get("line_offset", 0)
  
      ll_c = (center_point - east + 0.5 + column_offset) * column_step
      ll_l = (north - center_point + 0.5 + line_offset) * line_step
      ur_c = (center_point - west - 0.5 + column_offset) * column_step
      ur_l = (south - center_point - 0.5 + line_offset) * line_step
  
      return (ll_c, ll_l, ur_c, ur_l)
  
imports: from __future__ import annotations
  import warnings
  from datetime import datetime, timedelta
  import dask.array
  import numpy
  import pyproj
  from numpy.polynomial.chebyshev import Chebyshev
  from satpy.readers.eum_base import issue_revision, time_cds_short
  from satpy.readers.utils import apply_earthsun_distance_correction
  from satpy.utils import get_legacy_chunk_size
label_desc: Use image node_id 9 for calling a global function with example usage: calculate_area_extent(area_dict) and returns: ll_c,  ll_l,  ur_c,  ur_l