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 column_length(self, column: int) -> int:
      start, end = self.column_ranges[column]
      return gtz(end - start)
  
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 4 for calling the CRWindow obj's underlying member method code with example usage: obj.column_length(column) and returns: gtz