code: def sequential_filenames():
      """
      Generate filenames for the tests
      """
      for i in range(100):
          yield Path(f"filename-{i}.png")
  
file_path: plotnine/tests/test_save_as_pdf_pages.py
imports: import warnings
  from pathlib import Path
  import matplotlib.pyplot
  import pytest
  from plotnine import aes, geom_text, ggplot, ggtitle, theme
  from plotnine.data import mtcars
  from plotnine.exceptions import PlotnineError, PlotnineWarning
  from plotnine.ggplot import save_as_pdf_pages
label_desc: Use image node_id 2 for calling a global function with example usage: sequential_filenames() without return types