code: def test_use14corefonts():
      rcParams["pdf.use14corefonts"] = True
      rcParams["font.family"] = "sans-serif"
      rcParams["font.size"] = 8
      rcParams["font.sans-serif"] = ["Helvetica"]
      rcParams["pdf.compression"] = 0
  
      text = '''A three-line text positioned just above a blue line
  and containing some French characters and the euro symbol:
  "Merci pépé pour les 10 €"'''
  
      fig, ax = plt.subplots()
      ax.set_title("Test PDF backend with option use14corefonts=True")
      ax.text(
          0.5,
          0.5,
          text,
          horizontalalignment="center",
          verticalalignment="bottom",
          fontsize=14,
      )
      ax.axhline(0.5, linewidth=0.5)
  
imports: import datetime
  import decimal
  import io
  import os
  from pathlib import Path
  import numpy
  import pytest
  import matplotlib
  from matplotlib import pyplot, rcParams, font_manager
  from matplotlib.cbook import _get_data_path
  from matplotlib.ft2font import FT2Font
  from matplotlib.font_manager import findfont, FontProperties
  from matplotlib.backends._backend_pdf_ps import get_glyphs_subset
  from matplotlib.backends.backend_pdf import PdfPages
  from matplotlib.patches import Rectangle
  from matplotlib.testing.decorators import check_figures_equal, image_comparison
  from matplotlib.testing._markers import needs_usetex
label_desc: Use image node_id 1 for calling a global function with example usage: test_use14corefonts() without return types