code: def get_nonblank_lines(self):
      lines = self.get_all_lines()
      nonblank_lines = [l for l in lines if l.prelim_text.strip()]
      return nonblank_lines
  
imports: from collections import Counter
  from typing import List, Optional, Tuple
  from pydantic import BaseModel, field_validator
  import ftfy
  from marker.bbox import boxes_intersect_pct, multiple_boxes_intersect
  from marker.settings import settings
label_desc: Use image node_id 1 for calling the Page obj's underlying member method code with example usage: obj.get_nonblank_lines() and returns: nonblank_lines