class_docstr: Compressed row representation window.
  Stores the range of active grid cells in each column.
  Any window with contiguous columns can be expressed as a CRWindow.
  Supports efficient iterative construction and updates.
code: def __len__(self):
      return self.length
  
imports: import array
  from abc import ABC, abstractmethod
  from math import atan, tan
  from typing import Tuple
  import numpy
  from darts.logging import raise_if, raise_if_not
label_desc: Use image node_id 9 for calling the CRWindow obj's underlying member method code with example usage: obj.__len__() and returns: self