code: def doall():
      # Colors used in Matplotlib online documentation.
      mpl_grey_rgb = (51 / 255, 51 / 255, 51 / 255)
  
      # Creating figure and axis.
      fig = plt.figure(figsize=(7, 7))
      ax = fig.add_axes(
          [0.01, 0.01, 0.98, 0.90], facecolor="white", frameon=True
      )
      ax.set_xlim(0, 1)
      ax.set_ylim(0, 1)
      ax.set_title(
          "Matplotlib's math rendering engine",
          color=mpl_grey_rgb,
          fontsize=14,
          weight="bold",
      )
      ax.set_xticks([])
      ax.set_yticks([])
  
      # Gap between lines in axes coords
      line_axesfrac = 1 / n_lines
  
      # Plot header demonstration formula.
      full_demo = mathtext_demos["Header demo"]
      ax.annotate(
          full_demo,
          xy=(0.5, 1.0 - 0.59 * line_axesfrac),
          color="tab:orange",
          ha="center",
          fontsize=20,
      )
  
      # Plot feature demonstration formulae.
      for i_line, (title, demo) in enumerate(mathtext_demos.items()):
          print(i_line, demo)
          if i_line == 0:
              continue
  
          baseline = 1 - i_line * line_axesfrac
          baseline_next = baseline - line_axesfrac
          fill_color = ["white", "tab:blue"][i_line % 2]
          ax.axhspan(
              baseline, baseline_next, color=fill_color, alpha=0.2
          )
          ax.annotate(
              f"{title}:",
              xy=(0.06, baseline - 0.3 * line_axesfrac),
              color=mpl_grey_rgb,
              weight="bold",
          )
          ax.annotate(
              demo,
              xy=(0.04, baseline - 0.75 * line_axesfrac),
              color=mpl_grey_rgb,
              fontsize=16,
          )
  
      plt.show()
  
imports: import re
  import subprocess
  import sys
  import matplotlib.pyplot
label_desc: Use image node_id 1 for calling a global function with example usage: doall() without return types