code: def compute_skew(theta):
      # We assume a perfectly aligned page has lines at theta = 90 deg
      diff = 90 - theta
  
      # We want to reverse the difference.
      return -diff
  
imports: import os
  import traceback
  import sys
  import cv2
  import numpy
  from PIL import Image
  from scipy.ndimage.filters import rank_filter
  import pytesseract
label_desc: Use image node_id 18 for calling a global function with example usage: compute_skew(theta) and returns: unknown